contains 234 rules |
System Settings
[ref]groupContains rules that check correct system settings. |
contains 206 rules |
Installing and Maintaining Software
[ref]groupThe following sections contain information on
security-relevant choices during the initial operating system
installation process and the setup of software
updates. |
contains 26 rules |
System and Software Integrity
[ref]groupSystem and software integrity can be gained by installing antivirus, increasing
system encryption strength with FIPS, verifying installed software, enabling SELinux,
installing an Intrusion Prevention System, etc. However, installing or enabling integrity
checking tools cannot prevent intrusions, but they can detect that an intrusion
may have occurred. Requirements for integrity checking may be highly dependent on
the environment in which the system will be used. Snapshot-based approaches such
as AIDE may induce considerable overhead in the presence of frequent software updates. |
contains 7 rules |
Software Integrity Checking
[ref]groupBoth the AIDE (Advanced Intrusion Detection Environment)
software and the RPM package management system provide
mechanisms for verifying the integrity of installed software.
AIDE uses snapshots of file metadata (such as hashes) and compares these
to current system files in order to detect changes.
The RPM package management system can conduct integrity
checks by comparing information in its metadata database with
files installed on the system. |
contains 5 rules |
Verify Integrity with AIDE
[ref]groupAIDE conducts integrity checks by comparing information about
files with previously-gathered information. Ideally, the AIDE database is
created immediately after initial system configuration, and then again after any
software update. AIDE is highly configurable, with further configuration
information located in /usr/share/doc/aide-VERSION . |
contains 5 rules |
Install AIDE
[ref]ruleThe aide package can be installed with the following command:
$ sudo zypper install aide Rationale:The AIDE package must be installed if it is to be available for integrity checking. Identifiers:
CCE-83289-9 References:
BP28(R51), 1.4.1, 1, 11, 12, 13, 14, 15, 16, 2, 3, 5, 7, 8, 9, 5.10.1.3, APO01.06, BAI01.06, BAI02.01, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS04.07, DSS05.02, DSS05.03, DSS05.05, DSS05.07, DSS06.02, DSS06.06, CCI-002699, CCI-001744, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 4.1, SR 6.2, SR 7.6, 1034, 1288, 1341, 1417, A.11.2.4, A.12.1.2, A.12.2.1, A.12.4.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.14.2.7, A.15.2.1, A.8.2.3, CM-6(a), DE.CM-1, DE.CM-7, PR.DS-1, PR.DS-6, PR.DS-8, PR.IP-1, PR.IP-3, Req-11.5, SRG-OS-000363-GPOS-00150, SLES-15-010420, SV-234851r622137_rule Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
zypper install -y "aide"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
- name: Ensure aide is installed
package:
name: aide
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83289-9
- CJIS-5.10.1.3
- DISA-STIG-SLES-15-010420
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-11.5
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_aide_installed
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include install_aide
class install_aide {
package { 'aide':
ensure => 'installed',
}
}
Remediation script: (show)
[[packages]]
name = "aide"
version = "*"
|
Configure AIDE to Verify the Audit Tools
[ref]ruleThe operating system file integrity tool must be configured to protect the integrity of the audit tools. Rationale:Protecting the integrity of the tools used for auditing purposes is a
critical step toward ensuring the integrity of audit information. Audit
information includes all information (e.g., audit records, audit settings,
and audit reports) needed to successfully audit information system
activity.
Audit tools include but are not limited to vendor-provided and open-source
audit tools needed to successfully view and manipulate audit information
system activity and records. Audit tools include custom queries and report
generators.
It is not uncommon for attackers to replace the audit tools or inject code
into the existing tools to provide the capability to hide or erase system
activity from the audit logs.
To address this risk, audit tools must be cryptographically signed to
provide the capability to identify when the audit tools have been modified,
manipulated, or replaced. An example is a checksum hash of the file or
files. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Ensure aide is installed
package:
name: '{{ item }}'
state: present
with_items:
- aide
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85610-4
- DISA-STIG-SLES-15-030630
- NIST-800-53-AU-9(3)
- NIST-800-53-AU-9(3).1
- aide_check_audit_tools
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set audit_tools fact
set_fact:
audit_tools:
- /usr/sbin/audispd
- /usr/sbin/auditctl
- /usr/sbin/auditd
- /usr/sbin/augenrules
- /usr/sbin/aureport
- /usr/sbin/ausearch
- /usr/sbin/autrace
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85610-4
- DISA-STIG-SLES-15-030630
- NIST-800-53-AU-9(3)
- NIST-800-53-AU-9(3).1
- aide_check_audit_tools
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure existing AIDE configuration for audit tools are correct
lineinfile:
path: /etc/aide.conf
regexp: ^{{ item }}\s
line: '{{ item }} p+i+n+u+g+s+b+acl+selinux+xattrs+sha512'
with_items: '{{ audit_tools }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85610-4
- DISA-STIG-SLES-15-030630
- NIST-800-53-AU-9(3)
- NIST-800-53-AU-9(3).1
- aide_check_audit_tools
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Configure AIDE to properly protect audit tools
lineinfile:
path: /etc/aide.conf
line: '{{ item }} p+i+n+u+g+s+b+acl+selinux+xattrs+sha512'
with_items: '{{ audit_tools }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85610-4
- DISA-STIG-SLES-15-030630
- NIST-800-53-AU-9(3)
- NIST-800-53-AU-9(3).1
- aide_check_audit_tools
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Configure Periodic Execution of AIDE
[ref]ruleAt a minimum, AIDE should be configured to run a weekly scan.
To implement a daily execution of AIDE at 4:05am using cron, add the following line to /etc/crontab :
05 4 * * * root --check
To implement a weekly execution of AIDE at 4:05am using cron, add the following line to /etc/crontab :
05 4 * * 0 root --check
AIDE can be executed periodically through other means; this is merely one example.
The usage of cron's special time codes, such as @daily and
@weekly is acceptable.Rationale:By default, AIDE does not install itself for periodic execution. Periodically
running AIDE is necessary to reveal unexpected changes in installed files.
Unauthorized changes to the baseline configuration could make the system vulnerable
to various attacks or allow unauthorized access to the operating system. Changes to
operating system configurations can have unintended side effects, some of which may
be relevant to security.
Detecting such changes and providing an automated response can help avoid unintended,
negative consequences that could ultimately affect the security state of the operating
system. The operating system's Information Management Officer (IMO)/Information System
Security Officer (ISSO) and System Administrators (SAs) must be notified via email and/or
monitoring system trap when there is an unauthorized modification of a configuration item. Identifiers:
CCE-85671-6 References:
BP28(R51), 1.4.2, 1, 11, 12, 13, 14, 15, 16, 2, 3, 5, 7, 8, 9, 5.10.1.3, APO01.06, BAI01.06, BAI02.01, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS04.07, DSS05.02, DSS05.03, DSS05.05, DSS05.07, DSS06.02, DSS06.06, CCI-001744, CCI-002699, CCI-002702, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 4.1, SR 6.2, SR 7.6, A.11.2.4, A.12.1.2, A.12.2.1, A.12.4.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.14.2.7, A.15.2.1, A.8.2.3, SI-6(d), DE.CM-1, DE.CM-7, PR.DS-1, PR.DS-6, PR.DS-8, PR.IP-1, PR.IP-3, Req-11.5, SRG-OS-000363-GPOS-00150, SRG-OS-000446-GPOS-00200, SRG-OS-000447-GPOS-00201, SLES-15-010570, SV-234864r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
zypper install -y "aide"
if ! grep -q "/usr/bin/aide --check" /etc/crontab ; then
echo "05 4 * * * root /usr/bin/aide --check" >> /etc/crontab
else
sed -i '\!^.* --check.*$!d' /etc/crontab
echo "05 4 * * * root /usr/bin/aide --check" >> /etc/crontab
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Ensure AIDE is installed
package:
name: '{{ item }}'
state: present
with_items:
- aide
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85671-6
- CJIS-5.10.1.3
- DISA-STIG-SLES-15-010570
- NIST-800-53-SI-6(d)
- PCI-DSS-Req-11.5
- aide_periodic_cron_checking
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set cron package name - RedHat
set_fact:
cron_pkg_name: cronie
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_os_family == "RedHat" or ansible_os_family == "Suse"
tags:
- CCE-85671-6
- CJIS-5.10.1.3
- DISA-STIG-SLES-15-010570
- NIST-800-53-SI-6(d)
- PCI-DSS-Req-11.5
- aide_periodic_cron_checking
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set cron package name - Debian
set_fact:
cron_pkg_name: cron
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_os_family == "Debian"
tags:
- CCE-85671-6
- CJIS-5.10.1.3
- DISA-STIG-SLES-15-010570
- NIST-800-53-SI-6(d)
- PCI-DSS-Req-11.5
- aide_periodic_cron_checking
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Install cron
package:
name: '{{ cron_pkg_name }}'
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85671-6
- CJIS-5.10.1.3
- DISA-STIG-SLES-15-010570
- NIST-800-53-SI-6(d)
- PCI-DSS-Req-11.5
- aide_periodic_cron_checking
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Configure Periodic Execution of AIDE
cron:
name: run AIDE check
minute: 5
hour: 4
weekday: 0
user: root
job: /usr/bin/aide --check
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85671-6
- CJIS-5.10.1.3
- DISA-STIG-SLES-15-010570
- NIST-800-53-SI-6(d)
- PCI-DSS-Req-11.5
- aide_periodic_cron_checking
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Configure AIDE to Verify Access Control Lists (ACLs)
[ref]ruleBy default, the acl option is added to the FIPSR ruleset in AIDE.
If using a custom ruleset or the acl option is missing, add acl
to the appropriate ruleset.
For example, add acl to the following line in /etc/aide.conf :
FIPSR = p+i+n+u+g+s+m+c+acl+selinux+xattrs+sha256
AIDE rules can be configured in multiple ways; this is merely one example that is already
configured by default.
The remediation provided with this rule adds acl to all rule sets available in
/etc/aide.conf Rationale:ACLs can provide permissions beyond those permitted through the file mode and must be
verified by the file integrity tools. Identifiers:
CCE-85623-7 References:
BP28(R51), 2, 3, APO01.06, BAI03.05, BAI06.01, DSS06.02, CCI-000366, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, A.11.2.4, A.12.2.1, A.12.5.1, A.14.1.2, A.14.1.3, A.14.2.4, SI-7, SI-7(1), CM-6(a), PR.DS-6, PR.DS-8, SRG-OS-000480-GPOS-00227, SLES-15-040040, SV-234986r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
zypper install -y "aide"
aide_conf="/etc/aide.conf"
groups=$(LC_ALL=C grep "^[A-Z][A-Za-z_]*" $aide_conf | grep -v "^ALLXTRAHASHES" | cut -f1 -d '=' | tr -d ' ' | sort -u)
for group in $groups
do
config=$(grep "^$group\s*=" $aide_conf | cut -f2 -d '=' | tr -d ' ')
if ! [[ $config = *acl* ]]
then
if [[ -z $config ]]
then
config="acl"
else
config=$config"+acl"
fi
fi
sed -i "s/^$group\s*=.*/$group = $config/g" $aide_conf
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather list of packages
package_facts:
manager: auto
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85623-7
- DISA-STIG-SLES-15-040040
- NIST-800-53-CM-6(a)
- NIST-800-53-SI-7
- NIST-800-53-SI-7(1)
- aide_verify_acls
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- restrict_strategy
- name: get rules groups
shell: |
set -o pipefail
LC_ALL=C grep "^[A-Z][A-Za-z_]*" /etc/aide.conf | grep -v "^ALLXTRAHASHES" | cut -f1 -d '=' | tr -d ' ' | sort -u || true
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '''aide'' in ansible_facts.packages'
register: find_rules_groups_results
tags:
- CCE-85623-7
- DISA-STIG-SLES-15-040040
- NIST-800-53-CM-6(a)
- NIST-800-53-SI-7
- NIST-800-53-SI-7(1)
- aide_verify_acls
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- restrict_strategy
- name: ensure the acl rule is present when aide is installed.
replace:
path: /etc/aide.conf
regexp: (^\s*{{ item }}\s*=\s*)(?!.*acl)([^\s]*)
replace: \g<1>\g<2>+acl
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '''aide'' in ansible_facts.packages'
with_items: '{{ find_rules_groups_results.stdout_lines | map(''trim'') | list }}'
tags:
- CCE-85623-7
- DISA-STIG-SLES-15-040040
- NIST-800-53-CM-6(a)
- NIST-800-53-SI-7
- NIST-800-53-SI-7(1)
- aide_verify_acls
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- restrict_strategy
|
Configure AIDE to Verify Extended Attributes
[ref]ruleBy default, the xattrs option is added to the FIPSR ruleset in AIDE.
If using a custom ruleset or the xattrs option is missing, add xattrs
to the appropriate ruleset.
For example, add xattrs to the following line in /etc/aide.conf :
FIPSR = p+i+n+u+g+s+m+c+acl+selinux+xattrs+sha256
AIDE rules can be configured in multiple ways; this is merely one example that is already
configured by default.
The remediation provided with this rule adds xattrs to all rule sets available in
/etc/aide.conf Rationale:Extended attributes in file systems are used to contain arbitrary data and file metadata
with security implications. Identifiers:
CCE-85624-5 References:
BP28(R51), 2, 3, APO01.06, BAI03.05, BAI06.01, DSS06.02, CCI-000366, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, A.11.2.4, A.12.2.1, A.12.5.1, A.14.1.2, A.14.1.3, A.14.2.4, SI-7, SI-7(1), CM-6(a), PR.DS-6, PR.DS-8, SRG-OS-000480-GPOS-00227, SLES-15-040050, SV-234987r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
zypper install -y "aide"
aide_conf="/etc/aide.conf"
groups=$(LC_ALL=C grep "^[A-Z][A-Za-z_]*" $aide_conf | grep -v "^ALLXTRAHASHES" | cut -f1 -d '=' | tr -d ' ' | sort -u)
for group in $groups
do
config=$(grep "^$group\s*=" $aide_conf | cut -f2 -d '=' | tr -d ' ')
if ! [[ $config = *xattrs* ]]
then
if [[ -z $config ]]
then
config="xattrs"
else
config=$config"+xattrs"
fi
fi
sed -i "s/^$group\s*=.*/$group = $config/g" $aide_conf
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather list of packages
package_facts:
manager: auto
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85624-5
- DISA-STIG-SLES-15-040050
- NIST-800-53-CM-6(a)
- NIST-800-53-SI-7
- NIST-800-53-SI-7(1)
- aide_verify_ext_attributes
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- restrict_strategy
- name: get rules groups
shell: |
set -o pipefail
LC_ALL=C grep "^[A-Z][A-Za-z_]*" /etc/aide.conf | grep -v "^ALLXTRAHASHES" | cut -f1 -d '=' | tr -d ' ' | sort -u || true
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '''aide'' in ansible_facts.packages'
register: find_rules_groups_results
tags:
- CCE-85624-5
- DISA-STIG-SLES-15-040050
- NIST-800-53-CM-6(a)
- NIST-800-53-SI-7
- NIST-800-53-SI-7(1)
- aide_verify_ext_attributes
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- restrict_strategy
- name: ensure the xattrs rule is present when aide is installed.
replace:
path: /etc/aide.conf
regexp: (^\s*{{ item }}\s*=\s*)(?!.*xattrs)([^\s]*)
replace: \g<1>\g<2>+xattrs
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '''aide'' in ansible_facts.packages'
with_items: '{{ find_rules_groups_results.stdout_lines | map(''trim'') | list }}'
tags:
- CCE-85624-5
- DISA-STIG-SLES-15-040050
- NIST-800-53-CM-6(a)
- NIST-800-53-SI-7
- NIST-800-53-SI-7(1)
- aide_verify_ext_attributes
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- restrict_strategy
|
Federal Information Processing Standard (FIPS)
[ref]groupThe Federal Information Processing Standard (FIPS) is a computer security standard which
is developed by the U.S. Government and industry working groups to validate the quality
of cryptographic modules. The FIPS standard provides four security levels to ensure
adequate coverage of different industries, implementation of cryptographic modules, and
organizational sizes and requirements.
FIPS 140-2 is the current standard for validating that mechanisms used to access cryptographic modules
utilize authentication that meets industry and government requirements. For government systems, this allows
Security Levels 1, 2, 3, or 4 for use on SUSE Linux Enterprise 15.
See http://csrc.nist.gov/publications/PubsFIPS.html for more information. |
contains 1 rule |
Verify '/proc/sys/crypto/fips_enabled' exists
[ref]ruleOn a system where FIPS 140-2 mode is enabled, /proc/sys/crypto/fips_enabled must exist.
To verify FIPS mode, run the following command:
cat /proc/sys/crypto/fips_enabled Warning:
To configure the OS to run in FIPS 140-2 mode, the kernel parameter "fips=1" needs to be added during its installation.
Enabling FIPS mode on a preexisting system involves a number of modifications to it. Refer to the vendor installation
guidances. Warning:
System Crypto Modules must be provided by a vendor that undergoes
FIPS-140 certifications.
FIPS-140 is applicable to all Federal agencies that use
cryptographic-based security systems to protect sensitive information
in computer and telecommunication systems (including voice systems) as
defined in Section 5131 of the Information Technology Management Reform
Act of 1996, Public Law 104-106. This standard shall be used in
designing and implementing cryptographic modules that Federal
departments and agencies operate or are operated for them under
contract. See https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.140-2.pdf
To meet this, the system has to have cryptographic software provided by
a vendor that has undergone this certification. This means providing
documentation, test results, design information, and independent third
party review by an accredited lab. While open source software is
capable of meeting this, it does not meet FIPS-140 unless the vendor
submits to this process. Rationale:Use of weak or untested encryption algorithms undermines the purposes of utilizing encryption to
protect data. The operating system must implement cryptographic modules adhering to the higher
standards approved by the federal government since this provides assurance they have been tested
and validated. |
Operating System Vendor Support and Certification
[ref]groupThe assurance of a vendor to provide operating system support and maintenance
for their product is an important criterion to ensure product stability and
security over the life of the product. A certified product that follows the
necessary standards and government certification requirements guarantees that
known software vulnerabilities will be remediated, and proper guidance for
protecting and securing the operating system will be given. |
contains 1 rule |
The Installed Operating System Is Vendor Supported
[ref]ruleThe installed operating system must be maintained by a vendor.
SUSE Linux Enterprise is supported by SUSE. As the SUSE Linux Enterprise
vendor, SUSE is responsible for providing security patches. Warning:
There is no remediation besides switching to a different operating system. Rationale:An operating system is considered "supported" if the vendor continues to
provide security patches for the product. With an unsupported release, it
will not be possible to resolve any security issue discovered in the system
software. Identifiers:
CCE-83260-0 References:
18, 20, 4, APO12.01, APO12.02, APO12.03, APO12.04, BAI03.10, DSS05.01, DSS05.02, CCI-000366, 4.2.3, 4.2.3.12, 4.2.3.7, 4.2.3.9, A.12.6.1, A.14.2.3, A.16.1.3, A.18.2.2, A.18.2.3, CM-6(a), MA-6, SA-13(a), ID.RA-1, PR.IP-12, SRG-OS-000480-GPOS-00227, SLES-15-010000, SV-234800r622137_rule |
Disk Partitioning
[ref]groupTo ensure separation and protection of data, there
are top-level system directories which should be placed on their
own physical partition or logical volume. The installer's default
partitioning scheme creates separate logical volumes for
/ , /boot , and swap .
- If starting with any of the default layouts, check the box to
\"Review and modify partitioning.\" This allows for the easy creation
of additional logical volumes inside the volume group already
created, though it may require making
/ 's logical volume smaller to
create space. In general, using logical volumes is preferable to
using partitions because they can be more easily adjusted
later. - If creating a custom layout, create the partitions mentioned in
the previous paragraph (which the installer will require anyway),
as well as separate ones described in the following sections.
If a system has already been installed, and the default
partitioning
scheme was used, it is possible but nontrivial to
modify it to create separate logical volumes for the directories
listed above. The Logical Volume Manager (LVM) makes this possible.
See the LVM HOWTO at
http://tldp.org/HOWTO/LVM-HOWTO/
for more detailed information on LVM. |
contains 4 rules |
Encrypt Partitions
[ref]ruleSUSE Linux Enterprise 15 natively supports partition encryption through the
Linux Unified Key Setup-on-disk-format (LUKS) technology. The easiest way to
encrypt a partition is during installation time.
For manual installations, select the Encrypt checkbox during
partition creation to encrypt the partition. When this
option is selected the system will prompt for a passphrase to use in
decrypting the partition. The passphrase will subsequently need to be entered manually
every time the system boots.
Detailed information on encrypting partitions using LUKS or LUKS ciphers can be found on
the SUSE Linux Enterprise 15 Documentation web site:
https://www.suse.com/documentation/sled-12/book_security/data/sec_security_cryptofs_y2.html Rationale:The risk of a system's physical compromise, particularly mobile systems such as
laptops, places its data at risk of compromise. Encrypting this data mitigates
the risk of its loss if the system is lost. Identifiers:
CCE-85719-3 References:
13, 14, APO01.06, BAI02.01, BAI06.01, DSS04.07, DSS05.03, DSS05.04, DSS05.07, DSS06.02, DSS06.06, 3.13.16, CCI-001199, CCI-002475, CCI-002476, 164.308(a)(1)(ii)(D), 164.308(b)(1), 164.310(d), 164.312(a)(1), 164.312(a)(2)(iii), 164.312(a)(2)(iv), 164.312(b), 164.312(c), 164.314(b)(2)(i), 164.312(d), SR 3.4, SR 4.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-3 R4.2, CIP-007-3 R5.1, SC-28, SC-28.1, PR.DS-1, PR.DS-5, SRG-OS-000405-GPOS-00184, SRG-OS-000185-GPOS-00079, SRG-OS-000404-GPOS-00183, SLES-15-010330, SV-234831r622137_rule, SRG-OS-000404-VMM-001650, SRG-OS-000405-VMM-001660 |
Ensure /home Located On Separate Partition
[ref]ruleIf user home directories will be stored locally, create a separate partition
for /home at installation time (or migrate it later using LVM). If
/home will be mounted from another system such as an NFS server, then
creating a separate partition is not necessary at installation time, and the
mountpoint can instead be configured later. Rationale:Ensuring that /home is mounted on its own partition enables the
setting of more restrictive mount options, and also helps ensure that
users cannot trivially fill partitions used for log or audit data storage. Identifiers:
CCE-85639-3 References:
BP28(R12), 1.1.17, 12, 15, 8, APO13.01, DSS05.02, CCI-000366, CCI-001208, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.13.1.1, A.13.2.1, A.14.1.3, CM-6(a), SC-5(2), PR.PT-4, SRG-OS-000480-GPOS-00227, SLES-15-040200, SV-235004r622137_rule |
Ensure /var Located On Separate Partition
[ref]ruleThe /var directory is used by daemons and other system
services to store frequently-changing data. Ensure that /var has its own partition
or logical volume at installation time, or migrate it using LVM. Rationale:Ensuring that /var is mounted on its own partition enables the
setting of more restrictive mount options. This helps protect
system services such as daemons or other programs which use it.
It is not uncommon for the /var directory to contain
world-writable directories installed by other software packages. Identifiers:
CCE-85640-1 References:
BP28(R12), 1.1.7, 12, 15, 8, APO13.01, DSS05.02, CCI-000366, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.13.1.1, A.13.2.1, A.14.1.3, CM-6(a), SC-5(2), PR.PT-4, SRG-OS-000480-GPOS-00227, SLES-15-040210, SV-235005r622137_rule, SRG-OS-000341-VMM-001220 |
Ensure /var/log/audit Located On Separate Partition
[ref]ruleAudit logs are stored in the /var/log/audit directory.
Ensure that /var/log/audit has its own partition or logical
volume at installation time, or migrate it using LVM.
Make absolutely certain that it is large enough to store all
audit logs that will be created by the auditing daemon. Rationale:Placing /var/log/audit in its own partition
enables better separation between audit files
and other files, and helps ensure that
auditing cannot be halted due to the partition running out
of space. Identifiers:
CCE-85618-7 References:
BP28(R43), 1.1.16, 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 8, APO11.04, APO13.01, BAI03.05, BAI04.04, DSS05.02, DSS05.04, DSS05.07, MEA02.01, CCI-000366, CCI-001849, 164.312(a)(2)(ii), 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.2, SR 7.6, A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.17.2.1, CIP-007-3 R6.5, CM-6(a), AU-4, SC-5(2), PR.DS-4, PR.PT-1, PR.PT-4, SRG-OS-000341-GPOS-00132, SRG-OS-000480-GPOS-00227, SLES-15-030810, SV-234980r622137_rule, SRG-OS-000341-VMM-001220 |
GNOME Desktop Environment
[ref]groupGNOME is a graphical desktop environment bundled with many Linux distributions that
allow users to easily interact with the operating system graphically rather than
textually. The GNOME Graphical Display Manager (GDM) provides login, logout, and user
switching contexts as well as display server management.
GNOME is developed by the GNOME Project and is considered the default
Red Hat Graphical environment.
For more information on GNOME and the GNOME Project, see https://www.gnome.org. |
contains 6 rules |
Configure GNOME Login Screen
[ref]groupIn the default GNOME desktop, the login is displayed after system boot
and can display user accounts, allow users to reboot the system, and allow users to
login automatically and/or with a guest account. The login screen should be configured
to prevent such behavior.
For more information about enforcing preferences in the GNOME3 environment using the DConf
configuration system, see https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/desktop_migration_and_administration_guide/> and the man page dconf(1) . |
contains 1 rule |
Disable GDM Unattended or Automatic Login
[ref]ruleThe GNOME Display Manager (GDM) can allow users to automatically login without
user interaction or credentials or unattended login. User should always be required to authenticate themselves
to the system that they are authorized to use. To disable user ability to automatically
login to the system, set the DISPLAYMANAGER_AUTOLOGIN=""
or DISPLAYMANAGER_PASSWORD_LESS_LOGIN="no" in the
/etc/sysconfig/displaymanager . For example:
DISPLAYMANAGER_AUTOLOGIN=""
DISPLAYMANAGER_PASSWORD_LESS_LOGIN="no" Rationale:Failure to restrict system access to authenticated users negatively impacts operating
system security. Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
if ! (sed -n '/^DISPLAYMANAGER_AUTOLOGIN=\"\"/p' /etc/sysconfig/displaymanager)
then
sed -i "s/^DISPLAYMANAGER_AUTOLOGIN=.*/DISPLAYMANAGER_AUTOLOGIN=\"\"/g" /etc/sysconfig/displaymanager
fi
if ! (sed -n '/^DISPLAYMANAGER_PASSWORD_LESS_LOGIN=\"no\"/p' /etc/sysconfig/displaymanager)
then
sed -i "s/^DISPLAYMANAGER_PASSWORD_LESS_LOGIN=.*/DISPLAYMANAGER_PASSWORD_LESS_LOGIN=\"no\"/g" /etc/sysconfig/displaymanager
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85723-5
- DISA-STIG-SLES-15-040430
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- gnome_gdm_disable_unattended_automatic_login
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
- unknown_strategy
- name: Disable GDM Automatic Login
ini_file:
dest: /etc/sysconfig/displaymanager
section: null
option: DISPLAYMANAGER_AUTOLOGIN
value: '""'
no_extra_spaces: true
create: false
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85723-5
- DISA-STIG-SLES-15-040430
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- gnome_gdm_disable_unattended_automatic_login
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
- unknown_strategy
- name: Disable password less Login
ini_file:
dest: /etc/sysconfig/displaymanager
section: null
option: DISPLAYMANAGER_PASSWORD_LESS_LOGIN
value: '"no"'
no_extra_spaces: true
create: false
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85723-5
- DISA-STIG-SLES-15-040430
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- gnome_gdm_disable_unattended_automatic_login
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
- unknown_strategy
|
Configure GNOME Screen Locking
[ref]groupIn the default GNOME3 desktop, the screen can be locked
by selecting the user name in the far right corner of the main panel and
selecting Lock.
The following sections detail commands to enforce idle activation of the screensaver,
screen locking, a blank-screen screensaver, and an idle activation time.
Because users should be trained to lock the screen when they
step away from the computer, the automatic locking feature is only
meant as a backup.
The root account can be screen-locked; however, the root account should
never be used to log into an X Windows environment and should only
be used to for direct login via console in emergency circumstances.
For more information about enforcing preferences in the GNOME3 environment using the DConf
configuration system, see http://wiki.gnome.org/dconf and
the man page dconf(1) . |
contains 3 rules |
Set GNOME3 Screensaver Inactivity Timeout
[ref]ruleThe idle time-out value for inactivity in the GNOME3 desktop is configured via the idle-delay
setting must be set under an appropriate configuration file(s) in the /etc/dconf/db/local.d directory
and locked in /etc/dconf/db/local.d/locks directory to prevent user modification.
For example, to configure the system for a 15 minute delay, add the following to
/etc/dconf/db/local.d/00-security-settings :
[org/gnome/desktop/session]
idle-delay=uint32 900
Once the setting has been added, add a lock to
/etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification.
For example:
/org/gnome/desktop/session/idle-delay
After the settings have been set, run dconf update .Rationale:A session time-out lock is a temporary action taken when a user stops work and moves away from
the immediate physical vicinity of the information system but does not logout because of the
temporary nature of the absence. Rather than relying on the user to manually lock their operating
system session prior to vacating the vicinity, GNOME3 can be configured to identify when
a user's session has idled and take action to initiate a session lock. Identifiers:
CCE-85669-0 References:
1, 12, 15, 16, 5.5.5, DSS05.04, DSS05.10, DSS06.10, 3.1.10, CCI-000057, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, AC-11(a), AC-11.1 (ii), PR.AC-7, FMT_MOF_EXT.1, Req-8.1.8, SRG-OS-000029-GPOS-00010, SLES-15-010120, SV-234812r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
inactivity_timeout_value="900"
# Check for setting in any of the DConf db directories
# If files contain ibus or distro, ignore them.
# The assignment assumes that individual filenames don't contain :
readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/desktop/session\\]" "/etc/dconf/db/" | grep -v 'distro\|ibus' | cut -d":" -f1)
DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
DBDIR="/etc/dconf/db/local.d"
mkdir -p "${DBDIR}"
if [ "${#SETTINGSFILES[@]}" -eq 0 ]
then
[ ! -z ${DCONFFILE} ] || echo "" >> ${DCONFFILE}
printf '%s\n' "[org/gnome/desktop/session]" >> ${DCONFFILE}
printf '%s=%s\n' "idle-delay" "uint32 ${inactivity_timeout_value}" >> ${DCONFFILE}
else
escaped_value="$(sed -e 's/\\/\\\\/g' <<< "uint32 ${inactivity_timeout_value}")"
if grep -q "^\\s*idle-delay\\s*=" "${SETTINGSFILES[@]}"
then
sed -i "s/\\s*idle-delay\\s*=\\s*.*/idle-delay=${escaped_value}/g" "${SETTINGSFILES[@]}"
else
sed -i "\\|\\[org/gnome/desktop/session\\]|a\\idle-delay=${escaped_value}" "${SETTINGSFILES[@]}"
fi
fi
dconf update
# Check for setting in any of the DConf db directories
LOCKFILES=$(grep -r "^/org/gnome/desktop/session/idle-delay$" "/etc/dconf/db/" | grep -v 'distro\|ibus' | cut -d":" -f1)
LOCKSFOLDER="/etc/dconf/db/local.d/locks"
mkdir -p "${LOCKSFOLDER}"
if [[ -z "${LOCKFILES}" ]]
then
echo "/org/gnome/desktop/session/idle-delay" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
fi
dconf update
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85669-0
- CJIS-5.5.5
- DISA-STIG-SLES-15-010120
- NIST-800-171-3.1.10
- NIST-800-53-AC-11(a)
- NIST-800-53-AC-11.1 (ii)
- PCI-DSS-Req-8.1.8
- dconf_gnome_screensaver_idle_delay
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: XCCDF Value inactivity_timeout_value # promote to variable
set_fact:
inactivity_timeout_value: !!str 900
tags:
- always
- name: Set GNOME3 Screensaver Inactivity Timeout
ini_file:
dest: /etc/dconf/db/local.d/00-security-settings
section: org/gnome/desktop/session
option: idle-delay
value: uint32 {{ inactivity_timeout_value }}
create: true
no_extra_spaces: true
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85669-0
- CJIS-5.5.5
- DISA-STIG-SLES-15-010120
- NIST-800-171-3.1.10
- NIST-800-53-AC-11(a)
- NIST-800-53-AC-11.1 (ii)
- PCI-DSS-Req-8.1.8
- dconf_gnome_screensaver_idle_delay
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Prevent user modification of GNOME idle-delay
lineinfile:
path: /etc/dconf/db/local.d/locks/00-security-settings-lock
regexp: ^/org/gnome/desktop/session/idle-delay$
line: /org/gnome/desktop/session/idle-delay
create: true
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85669-0
- CJIS-5.5.5
- DISA-STIG-SLES-15-010120
- NIST-800-171-3.1.10
- NIST-800-53-AC-11(a)
- NIST-800-53-AC-11.1 (ii)
- PCI-DSS-Req-8.1.8
- dconf_gnome_screensaver_idle_delay
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Dconf Update
command: dconf update
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85669-0
- CJIS-5.5.5
- DISA-STIG-SLES-15-010120
- NIST-800-171-3.1.10
- NIST-800-53-AC-11(a)
- NIST-800-53-AC-11.1 (ii)
- PCI-DSS-Req-8.1.8
- dconf_gnome_screensaver_idle_delay
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
|
Enable GNOME3 Screensaver Lock After Idle Period
[ref]rule
To activate locking of the screensaver in the GNOME3 desktop when it is activated,
run the following command to configure the SUSE operating system to allow the user to lock the GUI:
gsettings set org.gnome.desktop.lockdown disable-lock-screen false
Validate that disable-lock-screen has been set to false with the command:
gsettings get org.gnome.desktop.lockdown disable-lock-screen Rationale:A session lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity
of the information system but does not want to logout because of the temporary nature of the absense. Identifiers:
CCE-85766-4 References:
1, 12, 15, 16, 5.5.5, DSS05.04, DSS05.10, DSS06.10, 3.1.10, CCI-000056, CCI-000058, CCI-000060, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, CM-6(a), PR.AC-7, FMT_MOF_EXT.1, Req-8.1.8, SRG-OS-000028-GPOS-00009, SRG-OS-000030-GPOS-00011, SLES-15-010100, SV-234810r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
gsettings set org.gnome.desktop.lockdown disable-lock-screen false
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85766-4
- CJIS-5.5.5
- DISA-STIG-SLES-15-010100
- NIST-800-171-3.1.10
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.8
- dconf_gnome_screensaver_lock_enabled
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Dconf Update
command: dconf update
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_distribution == 'SLES'
tags:
- CCE-85766-4
- CJIS-5.5.5
- DISA-STIG-SLES-15-010100
- NIST-800-171-3.1.10
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.8
- dconf_gnome_screensaver_lock_enabled
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Enable GNOME3 Screensaver Lock After Idle Period
ini_file:
dest: /etc/dconf/db/local.d/00-security-settings
section: org/gnome/desktop/screensaver
option: lock-enabled
value: 'true'
create: true
no_extra_spaces: true
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85766-4
- CJIS-5.5.5
- DISA-STIG-SLES-15-010100
- NIST-800-171-3.1.10
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.8
- dconf_gnome_screensaver_lock_enabled
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Prevent user modification of GNOME lock-enabled
lineinfile:
path: /etc/dconf/db/local.d/locks/00-security-settings-lock
regexp: ^/org/gnome/desktop/screensaver/lock-enabled$
line: /org/gnome/desktop/screensaver/lock-enabled
create: true
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85766-4
- CJIS-5.5.5
- DISA-STIG-SLES-15-010100
- NIST-800-171-3.1.10
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.8
- dconf_gnome_screensaver_lock_enabled
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Check GNOME3 screenserver disable-lock-screen false
command: gsettings get org.gnome.desktop.lockdown disable-lock-screen
register: cmd_out
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_distribution == 'SLES'
tags:
- CCE-85766-4
- CJIS-5.5.5
- DISA-STIG-SLES-15-010100
- NIST-800-171-3.1.10
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.8
- dconf_gnome_screensaver_lock_enabled
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Update GNOME3 screenserver disable-lock-screen false
command: gsettings set org.gnome.desktop.lockdown disable-lock-screen false
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ansible_distribution == 'SLES'
tags:
- CCE-85766-4
- CJIS-5.5.5
- DISA-STIG-SLES-15-010100
- NIST-800-171-3.1.10
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.8
- dconf_gnome_screensaver_lock_enabled
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Dconf Update
command: dconf update
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85766-4
- CJIS-5.5.5
- DISA-STIG-SLES-15-010100
- NIST-800-171-3.1.10
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.8
- dconf_gnome_screensaver_lock_enabled
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
|
Implement Blank Screensaver
[ref]rule
On SUSE users should set the screensaver to use publicly viewable images or blank screen
by doing the following:
Find the Settings menu and then navigate to the Background selection section
- Click "Activities" on the top left.
- Click "Show Applications" at the bottom of the Activities menu.
- Click the "Settings" icon.
- Click "Background" from left hand menu.
- Select image and set the Lock Screen image to the user's choice.
- Exit Settings Dialog.
To set the screensaver mode in the GNOME3 desktop to a blank screen,
add or set picture-uri to string '' in
/etc/dconf/db/local.d/00-security-settings . For example:
[org/gnome/desktop/screensaver]
picture-uri=''
Once the settings have been added, add a lock to
/etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification.
For example:
/org/gnome/desktop/screensaver/picture-uri
After the settings have been set, run dconf update .Rationale:Setting the screensaver mode to blank-only conceals the
contents of the display from passersby. Identifiers:
CCE-85715-1 References:
1, 12, 15, 16, 5.5.5, DSS05.04, DSS05.10, DSS06.10, 3.1.10, CCI-000060, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, AC-11(1), CM-6(a), AC-11(1).1, PR.AC-7, FMT_MOF_EXT.1, Req-8.1.8, SRG-OS-000031-GPOS-00012, SLES-15-010140, SV-234814r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
# Check for setting in any of the DConf db directories
# If files contain ibus or distro, ignore them.
# The assignment assumes that individual filenames don't contain :
readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/desktop/screensaver\\]" "/etc/dconf/db/" | grep -v 'distro\|ibus' | cut -d":" -f1)
DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
DBDIR="/etc/dconf/db/local.d"
mkdir -p "${DBDIR}"
if [ "${#SETTINGSFILES[@]}" -eq 0 ]
then
[ ! -z ${DCONFFILE} ] || echo "" >> ${DCONFFILE}
printf '%s\n' "[org/gnome/desktop/screensaver]" >> ${DCONFFILE}
printf '%s=%s\n' "picture-uri" "string ''" >> ${DCONFFILE}
else
escaped_value="$(sed -e 's/\\/\\\\/g' <<< "string ''")"
if grep -q "^\\s*picture-uri\\s*=" "${SETTINGSFILES[@]}"
then
sed -i "s/\\s*picture-uri\\s*=\\s*.*/picture-uri=${escaped_value}/g" "${SETTINGSFILES[@]}"
else
sed -i "\\|\\[org/gnome/desktop/screensaver\\]|a\\picture-uri=${escaped_value}" "${SETTINGSFILES[@]}"
fi
fi
dconf update
# Check for setting in any of the DConf db directories
LOCKFILES=$(grep -r "^/org/gnome/desktop/screensaver/picture-uri$" "/etc/dconf/db/" | grep -v 'distro\|ibus' | cut -d":" -f1)
LOCKSFOLDER="/etc/dconf/db/local.d/locks"
mkdir -p "${LOCKSFOLDER}"
if [[ -z "${LOCKFILES}" ]]
then
echo "/org/gnome/desktop/screensaver/picture-uri" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
fi
dconf update
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85715-1
- CJIS-5.5.5
- DISA-STIG-SLES-15-010140
- NIST-800-171-3.1.10
- NIST-800-53-AC-11(1)
- NIST-800-53-AC-11(1).1
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.8
- dconf_gnome_screensaver_mode_blank
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Implement Blank Screensaver
ini_file:
dest: /etc/dconf/db/local.d/00-security-settings
section: org/gnome/desktop/screensaver
option: picture-uri
value: string ''
create: true
no_extra_spaces: true
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85715-1
- CJIS-5.5.5
- DISA-STIG-SLES-15-010140
- NIST-800-171-3.1.10
- NIST-800-53-AC-11(1)
- NIST-800-53-AC-11(1).1
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.8
- dconf_gnome_screensaver_mode_blank
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Prevent user modification of GNOME picture-uri
lineinfile:
path: /etc/dconf/db/local.d/locks/00-security-settings-lock
regexp: ^/org/gnome/desktop/screensaver/picture-uri$
line: /org/gnome/desktop/screensaver/picture-uri
create: true
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85715-1
- CJIS-5.5.5
- DISA-STIG-SLES-15-010140
- NIST-800-171-3.1.10
- NIST-800-53-AC-11(1)
- NIST-800-53-AC-11(1).1
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.8
- dconf_gnome_screensaver_mode_blank
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Dconf Update
command: dconf update
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85715-1
- CJIS-5.5.5
- DISA-STIG-SLES-15-010140
- NIST-800-171-3.1.10
- NIST-800-53-AC-11(1)
- NIST-800-53-AC-11(1).1
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.1.8
- dconf_gnome_screensaver_mode_blank
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
|
Make sure that the dconf databases are up-to-date with regards to respective keyfiles
[ref]ruleBy default, DConf uses a binary database as a data backend.
The system-level database is compiled from keyfiles in the /etc/dconf/db/ directory by the dconf update command.Rationale:Unlike text-based keyfiles, the binary database is impossible to check by OVAL.
Therefore, in order to evaluate dconf configuration, both have to be true at the same time -
configuration files have to be compliant, and the database needs to be more recent than those keyfiles,
which gives confidence that it reflects them. Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
dconf update
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83288-1
- dconf_db_up_to_date
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
- unknown_strategy
- name: Run dconf update
shell: |-
set -o pipefail
dconf update
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83288-1
- dconf_db_up_to_date
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
- unknown_strategy
|
Configure GNOME3 DConf User Profile
[ref]ruleBy default, DConf provides a standard user profile. This profile contains a list
of DConf configuration databases. The user profile and database always take the
highest priority. As such the DConf User profile should always exist and be
configured correctly.
To make sure that the user profile is configured correctly, the /etc/dconf/profile/gdm
should be set as follows:
user-db:user
system-db:gdm
Rationale:Failure to have a functional DConf profile prevents GNOME3 configuration settings
from being enforced for all users and allows various security risks. Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
echo -e 'user-db:user\nsystem-db:gdm' > /etc/dconf/profile/gdm
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83267-5
- enable_dconf_user_profile
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
- unknown_strategy
- name: Configure GNOME3 DConf User Profile
lineinfile:
dest: /etc/dconf/profile/gdm
line: |-
user-db:user
system-db:gdm
create: true
state: present
when:
- '"gdm" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83267-5
- enable_dconf_user_profile
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
- unknown_strategy
|
Sudo , which stands for "su 'do'", provides the ability to delegate authority
to certain users, groups of users, or system administrators. When configured for system
users and/or groups, Sudo can allow a user or group to execute privileged commands
that normally only root is allowed to execute.
For more information on Sudo and addition Sudo configuration options, see
https://www.sudo.ws.
|
contains 6 rules |
Ensure Users Re-Authenticate for Privilege Escalation - sudo !authenticate
[ref]ruleThe sudo !authenticate option, when specified, allows a user to execute commands using
sudo without having to authenticate. This should be disabled by making sure that the
!authenticate option does not exist in /etc/sudoers configuration file or
any sudo configuration snippets in /etc/sudoers.d/ . Rationale:Without re-authentication, users may access resources or perform tasks for which they
do not have authorization.
When operating systems provide the capability to escalate a functional capability, it
is critical that the user re-authenticate. Identifiers:
CCE-83291-5 References:
BP28(R5), BP28(R59), 1, 12, 15, 16, 5, DSS05.04, DSS05.10, DSS06.03, DSS06.10, CCI-002038, 4.3.3.5.1, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-11, CM-6(a), PR.AC-1, PR.AC-7, SRG-OS-000373-GPOS-00156, SRG-OS-000373-GPOS-00157, SRG-OS-000373-GPOS-00158, SLES-15-010450, SV-234853r622137_rule, SRG-OS-000373-VMM-001470, SRG-OS-000373-VMM-001480, SRG-OS-000373-VMM-001490 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
for f in /etc/sudoers /etc/sudoers.d/* ; do
if [ ! -e "$f" ] ; then
continue
fi
matching_list=$(grep -P '^(?!#).*[\s]+\!authenticate.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "!authenticate" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
/usr/sbin/visudo -cf $f &> /dev/null || echo "Fail to validate $f with visudo"
fi
done
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Find /etc/sudoers.d/ files
find:
paths:
- /etc/sudoers.d/
register: sudoers
tags:
- CCE-83291-5
- DISA-STIG-SLES-15-010450
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-11
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_remove_no_authenticate
- name: Remove lines containing !authenticate from sudoers files
replace:
regexp: (^(?!#).*[\s]+\!authenticate.*$)
replace: '# \g<1>'
path: '{{ item.path }}'
validate: /usr/sbin/visudo -cf %s
with_items:
- path: /etc/sudoers
- '{{ sudoers.files }}'
tags:
- CCE-83291-5
- DISA-STIG-SLES-15-010450
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-11
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_remove_no_authenticate
|
Ensure Users Re-Authenticate for Privilege Escalation - sudo NOPASSWD
[ref]ruleThe sudo NOPASSWD tag, when specified, allows a user to execute
commands using sudo without having to authenticate. This should be disabled
by making sure that the NOPASSWD tag does not exist in
/etc/sudoers configuration file or any sudo configuration snippets
in /etc/sudoers.d/ . Rationale:Without re-authentication, users may access resources or perform tasks for which they
do not have authorization.
When operating systems provide the capability to escalate a functional capability, it
is critical that the user re-authenticate. Identifiers:
CCE-85663-3 References:
BP28(R5), BP28(R59), 1, 12, 15, 16, 5, DSS05.04, DSS05.10, DSS06.03, DSS06.10, CCI-002038, 4.3.3.5.1, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-11, CM-6(a), PR.AC-1, PR.AC-7, SRG-OS-000373-GPOS-00156, SRG-OS-000373-GPOS-00157, SRG-OS-000373-GPOS-00158, SLES-15-010450, SV-234853r622137_rule, SRG-OS-000373-VMM-001470, SRG-OS-000373-VMM-001480, SRG-OS-000373-VMM-001490 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
for f in /etc/sudoers /etc/sudoers.d/* ; do
if [ ! -e "$f" ] ; then
continue
fi
matching_list=$(grep -P '^(?!#).*[\s]+NOPASSWD[\s]*\:.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "NOPASSWD" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
/usr/sbin/visudo -cf $f &> /dev/null || echo "Fail to validate $f with visudo"
fi
done
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Find /etc/sudoers.d/ files
find:
paths:
- /etc/sudoers.d/
register: sudoers
tags:
- CCE-85663-3
- DISA-STIG-SLES-15-010450
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-11
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_remove_nopasswd
- name: Remove lines containing NOPASSWD from sudoers files
replace:
regexp: (^(?!#).*[\s]+NOPASSWD[\s]*\:.*$)
replace: '# \g<1>'
path: '{{ item.path }}'
validate: /usr/sbin/visudo -cf %s
with_items:
- path: /etc/sudoers
- '{{ sudoers.files }}'
tags:
- CCE-85663-3
- DISA-STIG-SLES-15-010450
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-11
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_remove_nopasswd
|
Ensure Users Re-Authenticate for Privilege Escalation - sudo
[ref]ruleThe sudo NOPASSWD and !authenticate option, when
specified, allows a user to execute commands using sudo without having to
authenticate. This should be disabled by making sure that
NOPASSWD and/or !authenticate do not exist in
/etc/sudoers configuration file or any sudo configuration snippets
in /etc/sudoers.d/ ." Rationale:Without re-authentication, users may access resources or perform tasks for which they
do not have authorization.
When operating systems provide the capability to escalate a functional capability, it
is critical that the user re-authenticate. Identifiers:
CCE-85673-2 References:
1, 12, 15, 16, 5, DSS05.04, DSS05.10, DSS06.03, DSS06.10, CCI-002038, 4.3.3.5.1, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-11, CM-6(a), PR.AC-1, PR.AC-7, SRG-OS-000373-GPOS-00156, SLES-15-010450, SV-234853r622137_rule Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
for f in /etc/sudoers /etc/sudoers.d/* ; do
if [ ! -e "$f" ] ; then
continue
fi
matching_list=$(grep -P '^(?!#).*[\s]+NOPASSWD[\s]*\:.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "NOPASSWD" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
/usr/sbin/visudo -cf $f &> /dev/null || echo "Fail to validate $f with visudo"
fi
done
for f in /etc/sudoers /etc/sudoers.d/* ; do
if [ ! -e "$f" ] ; then
continue
fi
matching_list=$(grep -P '^(?!#).*[\s]+\!authenticate.*$' $f | uniq )
if ! test -z "$matching_list"; then
while IFS= read -r entry; do
# comment out "!authenticate" matches to preserve user data
sed -i "s/^${entry}$/# &/g" $f
done <<< "$matching_list"
/usr/sbin/visudo -cf $f &> /dev/null || echo "Fail to validate $f with visudo"
fi
done
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Find /etc/sudoers.d/ files
find:
paths:
- /etc/sudoers.d/
register: sudoers
tags:
- CCE-85673-2
- DISA-STIG-SLES-15-010450
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-11
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_require_authentication
- name: Remove lines containing NOPASSWD from sudoers files
replace:
regexp: (^(?!#).*[\s]+NOPASSWD[\s]*\:.*$)
replace: '# \g<1>'
path: '{{ item.path }}'
validate: /usr/sbin/visudo -cf %s
with_items:
- path: /etc/sudoers
- '{{ sudoers.files }}'
tags:
- CCE-85673-2
- DISA-STIG-SLES-15-010450
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-11
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_require_authentication
- name: Find /etc/sudoers.d/ files
find:
paths:
- /etc/sudoers.d/
register: sudoers
tags:
- CCE-85673-2
- DISA-STIG-SLES-15-010450
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-11
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_require_authentication
- name: Remove lines containing !authenticate from sudoers files
replace:
regexp: (^(?!#).*[\s]+\!authenticate.*$)
replace: '# \g<1>'
path: '{{ item.path }}'
validate: /usr/sbin/visudo -cf %s
with_items:
- path: /etc/sudoers
- '{{ sudoers.files }}'
tags:
- CCE-85673-2
- DISA-STIG-SLES-15-010450
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-11
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_require_authentication
|
The operating system must require Re-Authentication when using the sudo command. Ensure sudo timestamp_timeout is appropriate - sudo timestamp_timeout
[ref]ruleThe sudo timestamp_timeout tag sets the amount of time sudo password prompt waits.
The default timestamp_timeout value is 5 minutes.
The timestamp_timeout should be configured by making sure that the
timestamp_timeout tag exists in
/etc/sudoers configuration file or any sudo configuration snippets
in /etc/sudoers.d/ .
If the value is set to an integer less than 0, the user's time stamp will not expire
and the user will not have to re-authenticate for privileged actions until the user's session is terminated. Rationale:Without re-authentication, users may access resources or perform tasks for which they
do not have authorization.
When operating systems provide the capability to escalate a functional capability, it
is critical that the user re-authenticate. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
var_sudo_timestamp_timeout="0"
if /usr/sbin/visudo -qcf /etc/sudoers; then
cp /etc/sudoers /etc/sudoers.bak
if ! grep -P '^[\s]*Defaults.*\btimestamp_timeout=[-]?\w+\b\b.*$' /etc/sudoers; then
# sudoers file doesn't define Option timestamp_timeout
echo "Defaults timestamp_timeout=${var_sudo_timestamp_timeout}" >> /etc/sudoers
else
# sudoers file defines Option timestamp_timeout, remediate if appropriate value is not set
if ! grep -P "^[\s]*Defaults.*\btimestamp_timeout=${var_sudo_timestamp_timeout}\b.*$" /etc/sudoers; then
sed -Ei "s/(^[\s]*Defaults.*\btimestamp_timeout=)[-]?\w+(\b.*$)/\1${var_sudo_timestamp_timeout}\2/" /etc/sudoers
fi
fi
# Check validity of sudoers and cleanup bak
if /usr/sbin/visudo -qcf /etc/sudoers; then
rm -f /etc/sudoers.bak
else
echo "Fail to validate remediated /etc/sudoers, reverting to original file."
mv /etc/sudoers.bak /etc/sudoers
false
fi
else
echo "Skipping remediation, /etc/sudoers failed to validate"
false
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_sudo_timestamp_timeout # promote to variable
set_fact:
var_sudo_timestamp_timeout: !!str 0
tags:
- always
- name: Ensure timestamp_timeout is enabled with the appropriate value in /etc/sudoers
lineinfile:
path: /etc/sudoers
regexp: ^[\s]*Defaults\s(.*)\btimestamp_timeout=[-]?\w+\b(.*)$
line: Defaults \1timestamp_timeout={{ var_sudo_timestamp_timeout }}\2
validate: /usr/sbin/visudo -cf %s
backrefs: true
register: edit_sudoers_timestamp_timeout_option
tags:
- CCE-85764-9
- DISA-STIG-SLES-15-020102
- NIST-800-53-IA-11
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_require_reauthentication
- name: Enable timestamp_timeout option with appropriate value in /etc/sudoers
lineinfile:
path: /etc/sudoers
line: Defaults timestamp_timeout={{ var_sudo_timestamp_timeout }}
validate: /usr/sbin/visudo -cf %s
when: edit_sudoers_timestamp_timeout_option is defined and not edit_sudoers_timestamp_timeout_option.changed
tags:
- CCE-85764-9
- DISA-STIG-SLES-15-020102
- NIST-800-53-IA-11
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudo_require_reauthentication
|
The operating system must restrict privilege elevation to authorized personnel
[ref]ruleThe sudo command allows a user to execute programs with elevated
(administrator) privileges. It prompts the user for their password
and confirms your request to execute a command by checking a file,
called sudoers.
Restrict privileged actions by removing the following entries from the sudoers file:
ALL ALL=(ALL) ALL
ALL ALL=(ALL:ALL) ALL Warning:
This rule doesn't come with a remediation, as the exact requirement allows exceptions,
and removing lines from the sudoers file can make the system non-administrable. Rationale:If the "sudoers" file is not configured correctly, any user defined
on the system can initiate privileged actions on the target system. |
Ensure invoking users password for privilege escalation when using sudo
[ref]ruleThe sudoers security policy requires that users authenticate themselves before they can use sudo.
When sudoers requires authentication, it validates the invoking user's credentials.
The expected output for:
sudo egrep -i '(!rootpw|!targetpw|!runaspw)' /etc/sudoers /etc/sudoers.d/* | grep -v '#'
/etc/sudoers:Defaults !targetpw
/etc/sudoers:Defaults !rootpw
/etc/sudoers:Defaults !runaspw Rationale:If the rootpw, targetpw, or runaspw flags are defined and not disabled, by default the operating system will prompt
the invoking user for the "root" user password. Remediation Shell script: (show)
if [ -e "/etc/sudoers" ] ; then
LC_ALL=C sed -i "/Defaults !targetpw/d" "/etc/sudoers"
else
touch "/etc/sudoers"
fi
cp "/etc/sudoers" "/etc/sudoers.bak"
# Insert at the end of the file
printf '%s\n' "Defaults !targetpw" >> "/etc/sudoers"
# Clean up after ourselves.
rm "/etc/sudoers.bak"
if [ -e "/etc/sudoers" ] ; then
LC_ALL=C sed -i "/Defaults !rootpw/d" "/etc/sudoers"
else
touch "/etc/sudoers"
fi
cp "/etc/sudoers" "/etc/sudoers.bak"
# Insert at the end of the file
printf '%s\n' "Defaults !rootpw" >> "/etc/sudoers"
# Clean up after ourselves.
rm "/etc/sudoers.bak"
if [ -e "/etc/sudoers" ] ; then
LC_ALL=C sed -i "/Defaults !runaspw/d" "/etc/sudoers"
else
touch "/etc/sudoers"
fi
cp "/etc/sudoers" "/etc/sudoers.bak"
# Insert at the end of the file
printf '%s\n' "Defaults !runaspw" >> "/etc/sudoers"
# Clean up after ourselves.
rm "/etc/sudoers.bak"
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Ensure that Defaults !targetpw is defined in sudoers
lineinfile:
path: /etc/sudoers
create: true
line: Defaults !targetpw
state: present
tags:
- CCE-85747-4
- DISA-STIG-SLES-15-020103
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudoers_validate_passwd
- name: Ensure that Defaults !rootpw is defined in sudoers
lineinfile:
path: /etc/sudoers
create: true
line: Defaults !rootpw
state: present
tags:
- CCE-85747-4
- DISA-STIG-SLES-15-020103
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudoers_validate_passwd
- name: Ensure that Defaults !runaspw is defined in sudoers
lineinfile:
path: /etc/sudoers
create: true
line: Defaults !runaspw
state: present
tags:
- CCE-85747-4
- DISA-STIG-SLES-15-020103
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sudoers_validate_passwd
|
Updating Software
[ref]groupThe zypper command line tool is used to install and
update software packages. The system also provides a graphical
software update tool in the System menu, in the Administration submenu,
called Software Update.
SUSE Linux Enterprise 15 systems contain an installed software catalog called
the RPM database, which records metadata of installed packages. Consistently using
zypper or the graphical Software Update for all software installation
allows for insight into the current inventory of installed software on the system.
|
contains 3 rules |
Ensure zypper Removes Previous Package Versions
[ref]rulezypper should be configured to remove previous software components after
new versions have been installed. To configure zypper to remove the
previous software components after updating, set the solver.upgradeRemoveDroppedPackages
to 1 in /etc/zypp/zypp.conf . Rationale:Previous versions of software components that are not removed from the information
system after updates have been installed may be exploited by some adversaries. Identifiers:
CCE-85551-0 References:
18, 20, 4, APO12.01, APO12.02, APO12.03, APO12.04, BAI03.10, DSS05.01, DSS05.02, 3.4.8, CCI-002617, 4.2.3, 4.2.3.12, 4.2.3.7, 4.2.3.9, A.12.6.1, A.14.2.3, A.16.1.3, A.18.2.2, A.18.2.3, SI-2(6), CM-11(a), CM-11(b), CM-6(a), ID.RA-1, PR.IP-12, SRG-OS-000437-GPOS-00194, SLES-15-010560, SV-234863r622137_rule, SRG-OS-000437-VMM-001760 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q yum; then
if grep --silent ^clean_requirements_on_remove /etc/yum.conf ; then
sed -i "s/^clean_requirements_on_remove.*/clean_requirements_on_remove=1/g" /etc/yum.conf
else
echo -e "\n# Set clean_requirements_on_remove to 1 per security requirements" >> /etc/yum.conf
echo "clean_requirements_on_remove=1" >> /etc/yum.conf
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85551-0
- DISA-STIG-SLES-15-010560
- NIST-800-171-3.4.8
- NIST-800-53-CM-11(a)
- NIST-800-53-CM-11(b)
- NIST-800-53-CM-6(a)
- NIST-800-53-SI-2(6)
- clean_components_post_updating
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure Zypper Removes Previous Package Versions
ini_file:
dest: /etc/zypp/zypp.conf
section: main
option: solver.upgradeRemoveDroppedPackages
value: true
create: false
when: '"yum" in ansible_facts.packages'
tags:
- CCE-85551-0
- DISA-STIG-SLES-15-010560
- NIST-800-171-3.4.8
- NIST-800-53-CM-11(a)
- NIST-800-53-CM-11(b)
- NIST-800-53-CM-6(a)
- NIST-800-53-SI-2(6)
- clean_components_post_updating
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- restrict_strategy
|
Ensure gpgcheck Enabled In Main zypper Configuration
[ref]ruleThe gpgcheck option controls whether
RPM packages' signatures are always checked prior to installation.
To configure zypper to check package signatures before installing
them, ensure the following line appears in /etc/zypp/zypp.conf in
the [main] section:
gpgcheck=1 Rationale:Changes to any software components can have significant effects on the
overall security of the operating system. This requirement ensures the
software has not been tampered with and that it has been provided by a
trusted vendor.
Accordingly, patches, service packs, device drivers, or operating system
components must be signed with a certificate recognized and approved by the
organization.
Verifying the authenticity of the software prior to installation
validates the integrity of the patch or upgrade received from a vendor.
This ensures the software has not been tampered with and that it has been
provided by a trusted vendor. Self-signed certificates are disallowed by
this requirement. Certificates used to verify the software must be from an
approved Certificate Authority (CA). Identifiers:
CCE-83290-7 References:
BP28(R15), 1.2.3, 11, 2, 3, 9, 5.10.4.1, APO01.06, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS06.02, 3.4.8, CCI-001749, 164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i), 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 7.6, A.11.2.4, A.12.1.2, A.12.2.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, CM-5(3), SI-7, SC-12, SC-12(3), CM-6(a), SA-12, SA-12(10), CM-11(a), CM-11(b), PR.DS-6, PR.DS-8, PR.IP-1, FPT_TUD_EXT.1, FPT_TUD_EXT.2, Req-6.2, SRG-OS-000366-GPOS-00153, SLES-15-010430, SV-234852r622137_rule, SRG-OS-000366-VMM-001430, SRG-OS-000370-VMM-001460, SRG-OS-000404-VMM-001650 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q zypper; then
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/zypp/zypp.conf"; then
sed_command+=('--follow-symlinks')
fi
# If the cce arg is empty, CCE is not assigned.
if [ -z "CCE-83290-7" ]; then
cce="CCE"
else
cce="CCE-83290-7"
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^gpgcheck")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "1"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^gpgcheck\\>" "/etc/zypp/zypp.conf"; then
"${sed_command[@]}" "s/^gpgcheck\\>.*/$formatted_output/gi" "/etc/zypp/zypp.conf"
else
# \n is precaution for case where file ends without trailing newline
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/zypp/zypp.conf" >> "/etc/zypp/zypp.conf"
printf '%s\n' "$formatted_output" >> "/etc/zypp/zypp.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83290-7
- CJIS-5.10.4.1
- DISA-STIG-SLES-15-010430
- NIST-800-171-3.4.8
- NIST-800-53-CM-11(a)
- NIST-800-53-CM-11(b)
- NIST-800-53-CM-5(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-SA-12
- NIST-800-53-SA-12(10)
- NIST-800-53-SC-12
- NIST-800-53-SC-12(3)
- NIST-800-53-SI-7
- PCI-DSS-Req-6.2
- ensure_gpgcheck_globally_activated
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
- unknown_strategy
- name: Ensure GPG check is globally activated (zypper)
ini_file:
dest: /etc/zypp/zypp.conf
section: main
option: gpgcheck
value: 1
no_extra_spaces: true
create: false
when: '"zypper" in ansible_facts.packages'
tags:
- CCE-83290-7
- CJIS-5.10.4.1
- DISA-STIG-SLES-15-010430
- NIST-800-171-3.4.8
- NIST-800-53-CM-11(a)
- NIST-800-53-CM-11(b)
- NIST-800-53-CM-5(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-SA-12
- NIST-800-53-SA-12(10)
- NIST-800-53-SC-12
- NIST-800-53-SC-12(3)
- NIST-800-53-SI-7
- PCI-DSS-Req-6.2
- ensure_gpgcheck_globally_activated
- high_severity
- low_complexity
- medium_disruption
- no_reboot_needed
- unknown_strategy
|
Ensure Software Patches Installed
[ref]rule
If the system is configured for online updates, invoking the following command will list available
security updates:
$ sudo zypper refresh && sudo zypper list-patches -g security
NOTE: U.S. Defense systems are required to be patched within 30 days or sooner as local policy
dictates.Rationale:Installing software updates is a fundamental mitigation against
the exploitation of publicly-known vulnerabilities. If the most
recent security patches and updates are not installed, unauthorized
users may take advantage of weaknesses in the unpatched software. The
lack of prompt attention to patching could result in a system compromise. Identifiers:
CCE-83261-8 References:
BP28(R08), 18, 20, 4, 5.10.4.1, APO12.01, APO12.02, APO12.03, APO12.04, BAI03.10, DSS05.01, DSS05.02, CCI-000366, CCI-001227, 4.2.3, 4.2.3.12, 4.2.3.7, 4.2.3.9, A.12.6.1, A.14.2.3, A.16.1.3, A.18.2.2, A.18.2.3, SI-2(5), SI-2(c), CM-6(a), ID.RA-1, PR.IP-12, FMT_MOF_EXT.1, Req-6.2, SRG-OS-000480-GPOS-00227, SLES-15-010010, SV-234802r622137_rule, SRG-OS-000480-VMM-002000 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | true |
---|
Strategy: | patch |
---|
zypper patch -g security -y
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Reboot: | true |
---|
Strategy: | patch |
---|
- name: Security patches are up to date
package:
name: '*'
state: latest
tags:
- CCE-83261-8
- CJIS-5.10.4.1
- DISA-STIG-SLES-15-010010
- NIST-800-53-CM-6(a)
- NIST-800-53-SI-2(5)
- NIST-800-53-SI-2(c)
- PCI-DSS-Req-6.2
- high_disruption
- high_severity
- low_complexity
- patch_strategy
- reboot_required
- security_patches_up_to_date
- skip_ansible_lint
|
Account and Access Control
[ref]groupIn traditional Unix security, if an attacker gains
shell access to a certain login account, they can perform any action
or access any file to which that account has access. Therefore,
making it more difficult for unauthorized people to gain shell
access to accounts, particularly to privileged accounts, is a
necessary part of securing a system. This section introduces
mechanisms for restricting access to accounts under
SUSE Linux Enterprise 15. |
contains 50 rules |
Warning Banners for System Accesses
[ref]groupEach system should expose as little information about
itself as possible.
System banners, which are typically displayed just before a
login prompt, give out information about the service or the host's
operating system. This might include the distribution name and the
system kernel version, and the particular version of a network
service. This information can assist intruders in gaining access to
the system as it can reveal whether the system is running
vulnerable software. Most network services can be configured to
limit what information is displayed.
Many organizations implement security policies that require a
system banner provide notice of the system's ownership, provide
warning to unauthorized users, and remind authorized users of their
consent to monitoring. |
contains 5 rules |
Implement a GUI Warning Banner
[ref]groupIn the default graphical environment, users logging
directly into the system are greeted with a login screen provided
by the GNOME Display Manager (GDM). The warning banner should be
displayed in this graphical environment for these users.
The following sections describe how to configure the GDM login
banner. |
contains 4 rules |
Modify the System GUI Login Banner
[ref]ruleTo configure the GUI system login banner edit /etc/gdm/banner .
Replace the default text with a message compliant with the local site
policy or a legal disclaimer.
The DoD required text is either:
You are accessing a U.S. Government (USG) Information System (IS) that
is provided for USG-authorized use only. By using this IS (which includes
any device attached to this IS), you consent to the following conditions:
-The USG routinely intercepts and monitors communications on this IS
for purposes including, but not limited to, penetration testing, COMSEC
monitoring, network operations and defense, personnel misconduct (PM), law
enforcement (LE), and counterintelligence (CI) investigations.
-At any time, the USG may inspect and seize data stored on this IS.
-Communications using, or data stored on, this IS are not private,
are subject to routine monitoring, interception, and search, and may be
disclosed or used for any USG-authorized purpose.
-This IS includes security measures (e.g., authentication and access
controls) to protect USG interests -- not for your personal benefit or
privacy.
-Notwithstanding the above, using this IS does not constitute consent
to PM, LE or CI investigative searching or monitoring of the content of
privileged communications, or work product, related to personal
representation or services by attorneys, psychotherapists, or clergy, and
their assistants. Such communications and work product are private and
confidential. See User Agreement for details.
OR:
I've read & consent to terms in IS user agreem't. Rationale:Display of a standardized and approved use notification before granting
access to the operating system ensures privacy and security notification
verbiage used is consistent with applicable federal laws, Executive Orders,
directives, policies, regulations, standards, and guidance.
System use notifications are required only for access via login interfaces
with human users and are not required when such human interfaces do not
exist. Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q gdm; then
login_banner_text="(N/A)"
# Multiple regexes transform the banner regex into a usable banner
# 0 - Remove anchors around the banner text
login_banner_text=$(echo "$login_banner_text" | sed 's/^\^\(.*\)\$$/\1/g')
# 1 - Keep only the first banners if there are multiple
# (dod_banners contains the long and short banner)
login_banner_text=$(echo "$login_banner_text" | sed 's/^(\(.*\)|.*)$/\1/g')
# 2 - Add spaces ' '. (Transforms regex for "space or newline" into a " ")
login_banner_text=$(echo "$login_banner_text" | sed 's/\[\\s\\n\]+/ /g')
# 3 - Adds newlines. (Transforms "(?:\[\\n\]+|(?:\\n)+)" into "\n")
login_banner_text=$(echo "$login_banner_text" | sed 's/(?:\[\\n\]+|(?:\\n)+)/\n/g')
# 4 - Remove any leftover backslash. (From any parethesis in the banner, for example).
login_banner_text=$(echo "$login_banner_text" | sed 's/\\//g')
formatted=$(echo "$login_banner_text" | fold -sw 80)
cat <<EOF >/etc/gdm/banner
$formatted
EOF
chmod 0644 /etc/gdm/banner
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83264-2
- DISA-STIG-SLES-15-010060
- NIST-800-53-AC-8(b)
- banner_etc_gdm_banner
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: XCCDF Value login_banner_text # promote to variable
set_fact:
login_banner_text: !!str (N/A)
tags:
- always
- name: Modify the System GUI Login Banner
lineinfile:
dest: /etc/gdm/banner
line: '{{ login_banner_text | regex_replace("^\^(.*)\$$", "\1") | regex_replace("^\((.*)\|.*\)$",
"\1") | regex_replace("\[\\s\\n\]\+"," ") | regex_replace("\(\?:\[\\n\]\+\|\(\?:\\\\n\)\+\)",
"\n") | regex_replace("\\", "") | wordwrap() }}'
create: true
when: '"gdm" in ansible_facts.packages'
tags:
- CCE-83264-2
- DISA-STIG-SLES-15-010060
- NIST-800-53-AC-8(b)
- banner_etc_gdm_banner
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
|
Enable GNOME3 Login Warning Banner
[ref]ruleIn the default graphical environment, displaying a login warning banner
in the GNOME Display Manager's login screen can be enabled on the login
screen by setting banner-message-enable to true .
To enable, add or edit banner-message-enable to
/etc/dconf/db/gdm.d/00-security-settings . For example:
[org/gnome/login-screen]
banner-message-enable=true
Once the setting has been added, add a lock to
/etc/dconf/db/gdm.d/locks/00-security-settings-lock to prevent user modification.
For example:
/org/gnome/login-screen/banner-message-enable
After the settings have been set, run dconf update .
The banner text must also be set.Rationale:Display of a standardized and approved use notification before granting access to the operating system
ensures privacy and security notification verbiage used is consistent with applicable federal laws,
Executive Orders, directives, policies, regulations, standards, and guidance.
For U.S. Government systems, system use notifications are required only for access via login interfaces
with human users and are not required when such human interfaces do not exist. Identifiers:
CCE-83265-9 References:
1.10, 1, 12, 15, 16, DSS05.04, DSS05.10, DSS06.10, 3.1.9, CCI-000048, CCI-000050, CCI-001384, CCI-001385, CCI-001386, CCI-001387, CCI-001388, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, AC-8(a), AC-8(b), AC-8(c), PR.AC-7, FMT_MOF_EXT.1, SRG-OS-000023-GPOS-00006, SRG-OS-000024-GPOS-00007, SRG-OS-000228-GPOS-00088, SLES-15-010080, SV-234808r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q gdm; then
# Check for setting in any of the DConf db directories
# If files contain ibus or distro, ignore them.
# The assignment assumes that individual filenames don't contain :
readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/login-screen\\]" "/etc/dconf/db/" | grep -v 'distro\|ibus' | cut -d":" -f1)
DCONFFILE="/etc/dconf/db/gdm.d/00-security-settings"
DBDIR="/etc/dconf/db/gdm.d"
mkdir -p "${DBDIR}"
if [ "${#SETTINGSFILES[@]}" -eq 0 ]
then
[ ! -z ${DCONFFILE} ] || echo "" >> ${DCONFFILE}
printf '%s\n' "[org/gnome/login-screen]" >> ${DCONFFILE}
printf '%s=%s\n' "banner-message-enable" "true" >> ${DCONFFILE}
else
escaped_value="$(sed -e 's/\\/\\\\/g' <<< "true")"
if grep -q "^\\s*banner-message-enable\\s*=" "${SETTINGSFILES[@]}"
then
sed -i "s/\\s*banner-message-enable\\s*=\\s*.*/banner-message-enable=${escaped_value}/g" "${SETTINGSFILES[@]}"
else
sed -i "\\|\\[org/gnome/login-screen\\]|a\\banner-message-enable=${escaped_value}" "${SETTINGSFILES[@]}"
fi
fi
dconf update
# Check for setting in any of the DConf db directories
LOCKFILES=$(grep -r "^/org/gnome/login-screen/banner-message-enable$" "/etc/dconf/db/" | grep -v 'distro\|ibus' | cut -d":" -f1)
LOCKSFOLDER="/etc/dconf/db/gdm.d/locks"
mkdir -p "${LOCKSFOLDER}"
if [[ -z "${LOCKFILES}" ]]
then
echo "/org/gnome/login-screen/banner-message-enable" >> "/etc/dconf/db/gdm.d/locks/00-security-settings-lock"
fi
dconf update
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83265-9
- DISA-STIG-SLES-15-010080
- NIST-800-171-3.1.9
- NIST-800-53-AC-8(a)
- NIST-800-53-AC-8(b)
- NIST-800-53-AC-8(c)
- dconf_gnome_banner_enabled
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Enable GNOME3 Login Warning Banner
ini_file:
dest: /etc/dconf/db/gdm.d/00-security-settings
section: org/gnome/login-screen
option: banner-message-enable
value: 'true'
create: true
no_extra_spaces: true
when: '"gdm" in ansible_facts.packages'
tags:
- CCE-83265-9
- DISA-STIG-SLES-15-010080
- NIST-800-171-3.1.9
- NIST-800-53-AC-8(a)
- NIST-800-53-AC-8(b)
- NIST-800-53-AC-8(c)
- dconf_gnome_banner_enabled
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Prevent user modification of GNOME banner-message-enabled
lineinfile:
path: /etc/dconf/db/gdm.d/locks/00-security-settings-lock
regexp: ^/org/gnome/login-screen/banner-message-enable$
line: /org/gnome/login-screen/banner-message-enable
create: true
when: '"gdm" in ansible_facts.packages'
tags:
- CCE-83265-9
- DISA-STIG-SLES-15-010080
- NIST-800-171-3.1.9
- NIST-800-53-AC-8(a)
- NIST-800-53-AC-8(b)
- NIST-800-53-AC-8(c)
- dconf_gnome_banner_enabled
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Dconf Update
command: dconf update
when: '"gdm" in ansible_facts.packages'
tags:
- CCE-83265-9
- DISA-STIG-SLES-15-010080
- NIST-800-171-3.1.9
- NIST-800-53-AC-8(a)
- NIST-800-53-AC-8(b)
- NIST-800-53-AC-8(c)
- dconf_gnome_banner_enabled
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
|
Set the GNOME3 Login Warning Banner Text
[ref]ruleIn the default graphical environment, configuring the login warning banner text
in the GNOME Display Manager's login screen can be configured on the login
screen by setting banner-message-text to 'APPROVED_BANNER'
where APPROVED_BANNER is the approved banner for your environment.
To enable, add or edit banner-message-text to
/etc/dconf/db/gdm.d/00-security-settings . For example:
[org/gnome/login-screen]
banner-message-text='APPROVED_BANNER'
Once the setting has been added, add a lock to
/etc/dconf/db/gdm.d/locks/00-security-settings-lock to prevent user modification.
For example:
/org/gnome/login-screen/banner-message-text
After the settings have been set, run dconf update .
When entering a warning banner that spans several lines, remember
to begin and end the string with ' and use \n for new lines.Rationale:An appropriate warning message reinforces policy awareness during the logon
process and facilitates possible legal action against attackers. Identifiers:
CCE-83266-7 References:
1.10, 1, 12, 15, 16, DSS05.04, DSS05.10, DSS06.10, 3.1.9, CCI-000048, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, AC-8(a), AC-8(c), PR.AC-7, FMT_MOF_EXT.1, SRG-OS-000023-GPOS-00006, SRG-OS-000024-GPOS-00007, SRG-OS-000228-GPOS-00088, SLES-15-010090, SV-234809r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q gdm; then
login_banner_text="(N/A)"
# Multiple regexes transform the banner regex into a usable banner
# 0 - Remove anchors around the banner text
login_banner_text=$(echo "$login_banner_text" | sed 's/^\^\(.*\)\$$/\1/g')
# 1 - Keep only the first banners if there are multiple
# (dod_banners contains the long and short banner)
login_banner_text=$(echo "$login_banner_text" | sed 's/^(\(.*\)|.*)$/\1/g')
# 2 - Add spaces ' '. (Transforms regex for "space or newline" into a " ")
login_banner_text=$(echo "$login_banner_text" | sed 's/\[\\s\\n\]+/ /g')
# 3 - Adds newline "tokens". (Transforms "(?:\[\\n\]+|(?:\\n)+)" into "(n)*")
login_banner_text=$(echo "$login_banner_text" | sed 's/(?:\[\\n\]+|(?:\\n)+)/(n)*/g')
# 4 - Remove any leftover backslash. (From any parethesis in the banner, for example).
login_banner_text=$(echo "$login_banner_text" | sed 's/\\//g')
# 5 - Removes the newline "token." (Transforms them into newline escape sequences "\n").
# ( Needs to be done after 4, otherwise the escapce sequence will become just "n".
login_banner_text=$(echo "$login_banner_text" | sed 's/(n)\*/\\n/g')
# Check for setting in any of the DConf db directories
# If files contain ibus or distro, ignore them.
# The assignment assumes that individual filenames don't contain :
readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/login-screen\\]" "/etc/dconf/db/" | grep -v 'distro\|ibus' | cut -d":" -f1)
DCONFFILE="/etc/dconf/db/gdm.d/00-security-settings"
DBDIR="/etc/dconf/db/gdm.d"
mkdir -p "${DBDIR}"
if [ "${#SETTINGSFILES[@]}" -eq 0 ]
then
[ ! -z ${DCONFFILE} ] || echo "" >> ${DCONFFILE}
printf '%s\n' "[org/gnome/login-screen]" >> ${DCONFFILE}
printf '%s=%s\n' "banner-message-text" "'${login_banner_text}'" >> ${DCONFFILE}
else
escaped_value="$(sed -e 's/\\/\\\\/g' <<< "'${login_banner_text}'")"
if grep -q "^\\s*banner-message-text\\s*=" "${SETTINGSFILES[@]}"
then
sed -i "s/\\s*banner-message-text\\s*=\\s*.*/banner-message-text=${escaped_value}/g" "${SETTINGSFILES[@]}"
else
sed -i "\\|\\[org/gnome/login-screen\\]|a\\banner-message-text=${escaped_value}" "${SETTINGSFILES[@]}"
fi
fi
dconf update
# Check for setting in any of the DConf db directories
LOCKFILES=$(grep -r "^/org/gnome/login-screen/banner-message-text$" "/etc/dconf/db/" | grep -v 'distro\|ibus' | cut -d":" -f1)
LOCKSFOLDER="/etc/dconf/db/gdm.d/locks"
mkdir -p "${LOCKSFOLDER}"
if [[ -z "${LOCKFILES}" ]]
then
echo "/org/gnome/login-screen/banner-message-text" >> "/etc/dconf/db/gdm.d/locks/00-security-settings-lock"
fi
dconf update
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83266-7
- DISA-STIG-SLES-15-010090
- NIST-800-171-3.1.9
- NIST-800-53-AC-8(a)
- NIST-800-53-AC-8(c)
- dconf_gnome_login_banner_text
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: XCCDF Value login_banner_text # promote to variable
set_fact:
login_banner_text: !!str (N/A)
tags:
- always
- name: Set the GNOME3 Login Warning Banner Text
file:
path: /etc/dconf/db/{{ item }}
owner: root
group: root
mode: 493
state: directory
with_items:
- gdm.d
- gdm.d/locks
when: '"gdm" in ansible_facts.packages'
tags:
- CCE-83266-7
- DISA-STIG-SLES-15-010090
- NIST-800-171-3.1.9
- NIST-800-53-AC-8(a)
- NIST-800-53-AC-8(c)
- dconf_gnome_login_banner_text
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Set the GNOME3 Login Warning Banner Text
file:
path: /etc/dconf/db/gdm.d/{{ item }}
owner: root
group: root
mode: 420
state: touch
with_items:
- 00-security-settings
- locks/00-security-settings-lock
when: '"gdm" in ansible_facts.packages'
tags:
- CCE-83266-7
- DISA-STIG-SLES-15-010090
- NIST-800-171-3.1.9
- NIST-800-53-AC-8(a)
- NIST-800-53-AC-8(c)
- dconf_gnome_login_banner_text
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Set the GNOME3 Login Warning Banner Text
ini_file:
dest: /etc/dconf/db/gdm.d/00-security-settings
section: org/gnome/login-screen
option: banner-message-text
value: '''{{ login_banner_text | regex_replace("^\^(.*)\$$", "\1") | regex_replace("^\((.*)\|.*\)$",
"\1") | regex_replace("\[\\s\\n\]\+"," ") | regex_replace("\(\?:\[\\n\]\+\|\(\?:\\\\n\)\+\)",
"(n)*") | regex_replace("\\", "") | regex_replace("\(n\)\*", "\\n") }}'''
create: true
no_extra_spaces: true
when: '"gdm" in ansible_facts.packages'
tags:
- CCE-83266-7
- DISA-STIG-SLES-15-010090
- NIST-800-171-3.1.9
- NIST-800-53-AC-8(a)
- NIST-800-53-AC-8(c)
- dconf_gnome_login_banner_text
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Prevent user modification of the GNOME3 Login Warning Banner Text
lineinfile:
path: /etc/dconf/db/gdm.d/locks/00-security-settings-lock
regexp: ^/org/gnome/login-screen/banner-message-text$
line: /org/gnome/login-screen/banner-message-text
create: true
state: present
when: '"gdm" in ansible_facts.packages'
tags:
- CCE-83266-7
- DISA-STIG-SLES-15-010090
- NIST-800-171-3.1.9
- NIST-800-53-AC-8(a)
- NIST-800-53-AC-8(c)
- dconf_gnome_login_banner_text
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Dconf Update
command: dconf update
when: '"gdm" in ansible_facts.packages'
tags:
- CCE-83266-7
- DISA-STIG-SLES-15-010090
- NIST-800-171-3.1.9
- NIST-800-53-AC-8(a)
- NIST-800-53-AC-8(c)
- dconf_gnome_login_banner_text
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
|
Display the Standard Mandatory DoD Notice and Consent Banner until Explicit Acknowledgement
[ref]ruleDisplay of a standardized and approved use notification before granting access to the SUSE operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance.
The banner must be acknowledged by the user prior to allowing the user access to the SUSE operating system. This provides assurance that the user has seen the message and accepted the conditions for access. If the consent banner is not acknowledged by the user, DoD will not be in compliance with system use notifications required by law.
System use notifications are required only for access via logon interfaces with human users and are not required when such human interfaces do not exist.
The banner must be formatted in accordance with applicable DoD policy. Use the following verbiage for the SUSE operating system:
You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only.
By using this IS (which includes any device attached to this IS), you consent to the following conditions:
-The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations.
-At any time, the USG may inspect and seize data stored on this IS.
-Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose.
-This IS includes security measures (e.g., authentication and access controls) to protect USG interests--not for your personal benefit or privacy.
-Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details.
Check the configuration by running the following command:
# more /etc/gdm/Xsession
The beginning of the file must contain the following text immediately after #!/bin/sh :
if ! zenity --text-info \
--title "Consent" \
--filename=/etc/gdm/banner \
--no-markup \
--checkbox="Accept." 10 10; then
sleep 1;
exit 1;
fi Rationale:Display of a standardized and approved use notification before granting access to the operating system
ensures privacy and security notification verbiage used is consistent with applicable federal laws,
Executive Orders, directives, policies, regulations, standards, and guidance.
For U.S. Government systems, system use notifications are required only for access via login interfaces
with human users and are not required when such human interfaces do not exist. Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q gdm; then
if ! [ -x /etc/gdm/Xsession ] ; then
echo "can only remediate if /etc/gdm/Xsession is an executable shell script" >&2
exit 1
fi
if ! awk 'NR==1 && $0 == "#!/bin/sh" { exit 0 } ; { exit 1 }' /etc/gdm/Xsession ; then
echo "can only remediate if /etc/gdm/Xsession is a shell script" >&2
exit 1
fi
f=$(mktemp)
echo '#!/bin/sh
if ! zenity --text-info \
--title "Consent" \
--filename=/etc/gdm/banner \
--no-markup \
--checkbox="Accept." 10 10; then
sleep 1;
exit 1;
fi
' > "$f"
# copy original contents of /etc/gdm/Xsession - but skip the shebang
tail -n +2 /etc/gdm/Xsession >> "$f"
chown --reference=/etc/gdm/Xsession "$f"
chmod --reference=/etc/gdm/Xsession "$f"
mv "$f" /etc/gdm/Xsession
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85668-2
- DISA-STIG-SLES-15-010050
- NIST-800-53-AC-8 a
- NIST-800-53-AC-8 b
- NIST-800-53-AC-8.1 (ii)
- NIST-800-53-AC-8.1 (iii)
- gui_login_dod_acknowledgement
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Validate /etc/gdm/Xsession is executable
stat:
path: /etc/gdm/Xsession
register: file_stat
when: '"gdm" in ansible_facts.packages'
tags:
- CCE-85668-2
- DISA-STIG-SLES-15-010050
- NIST-800-53-AC-8 a
- NIST-800-53-AC-8 b
- NIST-800-53-AC-8.1 (ii)
- NIST-800-53-AC-8.1 (iii)
- gui_login_dod_acknowledgement
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Validate /etc/gdm/Xsession is a shell script
lineinfile:
dest: /etc/gdm/Xsession
line: '#!/bin/sh'
check_mode: true
register: presence
when: '"gdm" in ansible_facts.packages'
tags:
- CCE-85668-2
- DISA-STIG-SLES-15-010050
- NIST-800-53-AC-8 a
- NIST-800-53-AC-8 b
- NIST-800-53-AC-8.1 (ii)
- NIST-800-53-AC-8.1 (iii)
- gui_login_dod_acknowledgement
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- name: Update file /etc/gdm/Xsession
blockinfile:
path: /etc/gdm/Xsession
block: |
if ! zenity --text-info \
--title "Consent" \
--filename=/etc/gdm/banner \
--no-markup \
--checkbox="Accept." 10 10; then
sleep 1;
exit 1;
fi
insertafter: '#!/bin/sh'
state: present
when:
- '"gdm" in ansible_facts.packages'
- not presence.changed | bool
- file_stat.stat.executable | bool
tags:
- CCE-85668-2
- DISA-STIG-SLES-15-010050
- NIST-800-53-AC-8 a
- NIST-800-53-AC-8 b
- NIST-800-53-AC-8.1 (ii)
- NIST-800-53-AC-8.1 (iii)
- gui_login_dod_acknowledgement
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
|
Modify the System Login Banner
[ref]ruleTo configure the system login banner edit /etc/issue . Replace the
default text with a message compliant with the local site policy or a legal
disclaimer.
The DoD required text is either:
You are accessing a U.S. Government (USG) Information System (IS) that
is provided for USG-authorized use only. By using this IS (which includes
any device attached to this IS), you consent to the following conditions:
-The USG routinely intercepts and monitors communications on this IS
for purposes including, but not limited to, penetration testing, COMSEC
monitoring, network operations and defense, personnel misconduct (PM), law
enforcement (LE), and counterintelligence (CI) investigations.
-At any time, the USG may inspect and seize data stored on this IS.
-Communications using, or data stored on, this IS are not private,
are subject to routine monitoring, interception, and search, and may be
disclosed or used for any USG-authorized purpose.
-This IS includes security measures (e.g., authentication and access
controls) to protect USG interests -- not for your personal benefit or
privacy.
-Notwithstanding the above, using this IS does not constitute consent
to PM, LE or CI investigative searching or monitoring of the content of
privileged communications, or work product, related to personal
representation or services by attorneys, psychotherapists, or clergy, and
their assistants. Such communications and work product are private and
confidential. See User Agreement for details.
OR:
I've read & consent to terms in IS user agreem't. Rationale:Display of a standardized and approved use notification before granting
access to the operating system ensures privacy and security notification
verbiage used is consistent with applicable federal laws, Executive Orders,
directives, policies, regulations, standards, and guidance.
System use notifications are required only for access via login interfaces
with human users and are not required when such human interfaces do not
exist. Identifiers:
CCE-83262-6 References:
1.8.1.2, 1, 12, 15, 16, DSS05.04, DSS05.10, DSS06.10, 3.1.9, CCI-000048, CCI-000050, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, AC-8(a), AC-8(c), PR.AC-7, FMT_MOF_EXT.1, SRG-OS-000023-GPOS-00006, SRG-OS-000024-GPOS-00007, SLES-15-010020, SV-234803r622137_rule, SRG-OS-000023-VMM-000060, SRG-OS-000024-VMM-000070 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
login_banner_text="(N/A)"
# Multiple regexes transform the banner regex into a usable banner
# 0 - Remove anchors around the banner text
login_banner_text=$(echo "$login_banner_text" | sed 's/^\^\(.*\)\$$/\1/g')
# 1 - Keep only the first banners if there are multiple
# (dod_banners contains the long and short banner)
login_banner_text=$(echo "$login_banner_text" | sed 's/^(\(.*\)|.*)$/\1/g')
# 2 - Add spaces ' '. (Transforms regex for "space or newline" into a " ")
login_banner_text=$(echo "$login_banner_text" | sed 's/\[\\s\\n\]+/ /g')
# 3 - Adds newlines. (Transforms "(?:\[\\n\]+|(?:\\n)+)" into "\n")
login_banner_text=$(echo "$login_banner_text" | sed 's/(?:\[\\n\]+|(?:\\n)+)/\n/g')
# 4 - Remove any leftover backslash. (From any parethesis in the banner, for example).
login_banner_text=$(echo "$login_banner_text" | sed 's/\\//g')
formatted=$(echo "$login_banner_text" | fold -sw 80)
cat <<EOF >/etc/issue
$formatted
EOF
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
- name: XCCDF Value login_banner_text # promote to variable
set_fact:
login_banner_text: !!str (N/A)
tags:
- always
- name: Modify the System Login Banner - ensure correct banner
copy:
dest: /etc/issue
content: '{{ login_banner_text | regex_replace("^\^(.*)\$$", "\1") | regex_replace("^\((.*)\|.*\)$",
"\1") | regex_replace("\[\\s\\n\]\+"," ") | regex_replace("\(\?:\[\\n\]\+\|\(\?:\\\\n\)\+\)",
"\n") | regex_replace("\\", "") | wordwrap() }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83262-6
- DISA-STIG-SLES-15-010020
- NIST-800-171-3.1.9
- NIST-800-53-AC-8(a)
- NIST-800-53-AC-8(c)
- banner_etc_issue
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
|
Protect Accounts by Configuring PAM
[ref]groupPAM, or Pluggable Authentication Modules, is a system
which implements modular authentication for Linux programs. PAM provides
a flexible and configurable architecture for authentication, and it should be configured
to minimize exposure to unnecessary risk. This section contains
guidance on how to accomplish that.
PAM is implemented as a set of shared objects which are
loaded and invoked whenever an application wishes to authenticate a
user. Typically, the application must be running as root in order
to take advantage of PAM, because PAM's modules often need to be able
to access sensitive stores of account information, such as /etc/shadow.
Traditional privileged network listeners
(e.g. sshd) or SUID programs (e.g. sudo) already meet this
requirement. An SUID root application, userhelper, is provided so
that programs which are not SUID or privileged themselves can still
take advantage of PAM.
PAM looks in the directory /etc/pam.d for
application-specific configuration information. For instance, if
the program login attempts to authenticate a user, then PAM's
libraries follow the instructions in the file /etc/pam.d/login
to determine what actions should be taken.
One very important file in /etc/pam.d is
/etc/pam.d/system-auth . This file, which is included by
many other PAM configuration files, defines 'default' system authentication
measures. Modifying this file is a good way to make far-reaching
authentication changes, for instance when implementing a
centralized authentication service. Warning:
Be careful when making changes to PAM's configuration files.
The syntax for these files is complex, and modifications can
have unexpected consequences. The default configurations shipped
with applications should be sufficient for most users. |
contains 15 rules |
Set Lockouts for Failed Password Attempts
[ref]groupThe pam_faillock PAM module provides the capability to
lock out user accounts after a number of failed login attempts. Its
documentation is available in
/usr/share/doc/pam-VERSION/txts/README.pam_faillock .
Warning:
Locking out user accounts presents the
risk of a denial-of-service attack. The lockout policy
must weigh whether the risk of such a
denial-of-service attack outweighs the benefits of thwarting
password guessing attacks. |
contains 3 rules |
Limit Password Reuse
[ref]ruleDo not allow users to reuse recent passwords. This can be
accomplished by using the remember option for the pam_unix
or pam_pwhistory PAM modules.
In the file /etc/pam.d/system-auth , append remember=5
to the line which refers to the pam_unix.so or pam_pwhistory.so module, as shown below:
The DoD STIG requirement is 5 passwords.Rationale:Preventing re-use of previous passwords helps ensure that a compromised password is not re-used by a user. Identifiers:
CCE-85678-1 References:
BP28(R18), 1, 12, 15, 16, 5, 5.6.2.1.1, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.5.8, CCI-000200, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(1)(e), IA-5(1).1(v), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.2.5, SRG-OS-000077-GPOS-00045, SLES-15-020250, SV-234894r622137_rule, SRG-OS-000077-VMM-000440 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85678-1
- CJIS-5.6.2.1.1
- DISA-STIG-SLES-15-020250
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(1).1(v)
- PCI-DSS-Req-8.2.5
- accounts_password_pam_unix_remember
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: XCCDF Value var_password_pam_unix_remember # promote to variable
set_fact:
var_password_pam_unix_remember: !!str 5
tags:
- always
- name: Do not allow users to reuse recent passwords - system-auth (change)
replace:
dest: /etc/pam.d/system-auth
regexp: ^(password\s+sufficient\s+pam_unix\.so\s.*remember\s*=\s*)(\S+)(.*)$
replace: \g<1>{{ var_password_pam_unix_remember }}\g<3>
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85678-1
- CJIS-5.6.2.1.1
- DISA-STIG-SLES-15-020250
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(1).1(v)
- PCI-DSS-Req-8.2.5
- accounts_password_pam_unix_remember
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- name: Do not allow users to reuse recent passwords - system-auth (add)
replace:
dest: /etc/pam.d/system-auth
regexp: ^password\s+sufficient\s+pam_unix\.so\s(?!.*remember\s*=\s*).*$
replace: \g<0> remember={{ var_password_pam_unix_remember }}
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85678-1
- CJIS-5.6.2.1.1
- DISA-STIG-SLES-15-020250
- NIST-800-171-3.5.8
- NIST-800-53-IA-5(1)(e)
- NIST-800-53-IA-5(1).1(v)
- PCI-DSS-Req-8.2.5
- accounts_password_pam_unix_remember
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
|
Enforce Delay After Failed Logon Attempts
[ref]ruleTo configure the system to introduce a delay after failed logon attempts,
add or correct the pam_faildelay settings in
/etc/pam.d/common-auth to make sure its delay parameter
is at least 4000000 or greater. For example:
auth required pam_faildelay.so delay=4000000 Rationale:Limiting the number of logon attempts over a certain time interval reduces
the chances that an unauthorized user may gain access to an account. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_password_pam_delay # promote to variable
set_fact:
var_password_pam_delay: !!str 4000000
tags:
- always
- name: Set control_flag fact
set_fact:
control_flag: required
tags:
- CCE-85619-5
- DISA-STIG-SLES-15-040000
- accounts_passwords_pam_faildelay_delay
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check to see if 'pam_faildelay.so' module is configured in '/etc/pam.d/common-auth'
shell: |
set -o pipefail
grep -E '^\s*auth\s+\S+\s+pam_faildelay.so' /etc/pam.d/common-auth || true
register: check_pam_module_result
tags:
- CCE-85619-5
- DISA-STIG-SLES-15-040000
- accounts_passwords_pam_faildelay_delay
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Configure 'pam_faildelay.so' module in '/etc/pam.d/common-auth'
lineinfile:
path: /etc/pam.d/common-auth
line: auth required pam_faildelay.so
state: present
when: '"pam_faildelay.so" not in check_pam_module_result.stdout'
tags:
- CCE-85619-5
- DISA-STIG-SLES-15-040000
- accounts_passwords_pam_faildelay_delay
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure 'pam_faildelay.so' module has conforming control flag
lineinfile:
path: /etc/pam.d/common-auth
regexp: ^(\s*auth\s+)\S+(\s+pam_faildelay.so\s+.*)
line: \g<1>required\g<2>
backrefs: true
when: control_flag|length
tags:
- CCE-85619-5
- DISA-STIG-SLES-15-040000
- accounts_passwords_pam_faildelay_delay
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure "pam_faildelay.so" module has argument "delay={{ var_password_pam_delay
}}"
lineinfile:
path: /etc/pam.d/common-auth
regexp: ^(\s*auth\s+required\s+pam_faildelay.so(?:\s+\S+)*\s+delay=)(?:\S+)((\s+\S+)*\s*\\*\s*)$
line: \g<1>{{ var_password_pam_delay }}\g<2>
backrefs: true
tags:
- CCE-85619-5
- DISA-STIG-SLES-15-040000
- accounts_passwords_pam_faildelay_delay
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check the presence of "delay" argument in "pam_faildelay.so" module
shell: |
set -o pipefail
grep -E '^\s*auth\s+required\s+pam_faildelay.so.*\s+delay(=|\s|\s*$)' /etc/pam.d/common-auth || true
register: check_pam_module_argument_result
tags:
- CCE-85619-5
- DISA-STIG-SLES-15-040000
- accounts_passwords_pam_faildelay_delay
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add "delay" argument to "pam_faildelay.so" module
lineinfile:
path: /etc/pam.d/common-auth
regexp: ^(\s*auth\s+required\s+pam_faildelay.so)((\s+\S+)*\s*(\\)*$)
line: \g<1> delay={{ var_password_pam_delay }}\g<2>
backrefs: true
when: '"delay" not in check_pam_module_argument_result.stdout'
tags:
- CCE-85619-5
- DISA-STIG-SLES-15-040000
- accounts_passwords_pam_faildelay_delay
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Set Deny For Failed Password Attempts
[ref]ruleThe SUSE Linux Enterprise 15 operating system must lock an account after - at most - 3
consecutive invalid access attempts. Rationale:By limiting the number of failed logon attempts, the risk of unauthorized
system access via user password guessing, otherwise known as brute-force
attacks, is reduced. Limits are imposed by locking the account.
To configure the operating system to lock an account after three
unsuccessful consecutive access attempts using pam_tally2.so ,
modify the content of both /etc/pam.d/common-auth and
/etc/pam.d/common-account as follows:
Remediation Shell script: (show)
var_password_pam_tally2="3"
# Use a non-number regexp to force update of the value of the deny option
if [ -e "/etc/pam.d/common-auth" ] ; then
valueRegex="X" defaultValue="${var_password_pam_tally2}"
# non-empty values need to be preceded by an equals sign
[ -n "${valueRegex}" ] && valueRegex="=${valueRegex}"
# add an equals sign to non-empty values
[ -n "${defaultValue}" ] && defaultValue="=${defaultValue}"
# fix 'type' if it's wrong
if grep -q -P "^\\s*(?"'!'"auth\\s)[[:alnum:]]+\\s+[[:alnum:]]+\\s+pam_tally2.so" < "/etc/pam.d/common-auth" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*)[[:alnum:]]+(\\s+[[:alnum:]]+\\s+pam_tally2.so)/\\1auth\\2/" "/etc/pam.d/common-auth"
fi
# fix 'control' if it's wrong
if grep -q -P "^\\s*auth\\s+(?"'!'"required)[[:alnum:]]+\\s+pam_tally2.so" < "/etc/pam.d/common-auth" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*auth\\s+)[[:alnum:]]+(\\s+pam_tally2.so)/\\1required\\2/" "/etc/pam.d/common-auth"
fi
# fix the value for 'option' if one exists but does not match 'valueRegex'
if grep -q -P "^\\s*auth\\s+required\\s+pam_tally2.so(\\s.+)?\\s+deny(?"'!'"${valueRegex}(\\s|\$))" < "/etc/pam.d/common-auth" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*auth\\s+required\\s+pam_tally2.so(\\s.+)?\\s)deny=[^[:space:]]*/\\1deny${defaultValue}/" "/etc/pam.d/common-auth"
# add 'option=default' if option is not set
elif grep -q -E "^\\s*auth\\s+required\\s+pam_tally2.so" < "/etc/pam.d/common-auth" &&
grep -E "^\\s*auth\\s+required\\s+pam_tally2.so" < "/etc/pam.d/common-auth" | grep -q -E -v "\\sdeny(=|\\s|\$)" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*auth\\s+required\\s+pam_tally2.so[^\\n]*)/\\1 deny${defaultValue}/" "/etc/pam.d/common-auth"
# add a new entry if none exists
elif ! grep -q -P "^\\s*auth\\s+required\\s+pam_tally2.so(\\s.+)?\\s+deny${valueRegex}(\\s|\$)" < "/etc/pam.d/common-auth" ; then
echo "auth required pam_tally2.so deny${defaultValue}" >> "/etc/pam.d/common-auth"
fi
else
echo "/etc/pam.d/common-auth doesn't exist" >&2
fi
if [ -e "/etc/pam.d/common-auth" ] ; then
valueRegex="(fail)" defaultValue="fail"
# non-empty values need to be preceded by an equals sign
[ -n "${valueRegex}" ] && valueRegex="=${valueRegex}"
# add an equals sign to non-empty values
[ -n "${defaultValue}" ] && defaultValue="=${defaultValue}"
# fix 'type' if it's wrong
if grep -q -P "^\\s*(?"'!'"auth\\s)[[:alnum:]]+\\s+[[:alnum:]]+\\s+pam_tally2.so" < "/etc/pam.d/common-auth" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*)[[:alnum:]]+(\\s+[[:alnum:]]+\\s+pam_tally2.so)/\\1auth\\2/" "/etc/pam.d/common-auth"
fi
# fix 'control' if it's wrong
if grep -q -P "^\\s*auth\\s+(?"'!'"required)[[:alnum:]]+\\s+pam_tally2.so" < "/etc/pam.d/common-auth" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*auth\\s+)[[:alnum:]]+(\\s+pam_tally2.so)/\\1required\\2/" "/etc/pam.d/common-auth"
fi
# fix the value for 'option' if one exists but does not match 'valueRegex'
if grep -q -P "^\\s*auth\\s+required\\s+pam_tally2.so(\\s.+)?\\s+onerr(?"'!'"${valueRegex}(\\s|\$))" < "/etc/pam.d/common-auth" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*auth\\s+required\\s+pam_tally2.so(\\s.+)?\\s)onerr=[^[:space:]]*/\\1onerr${defaultValue}/" "/etc/pam.d/common-auth"
# add 'option=default' if option is not set
elif grep -q -E "^\\s*auth\\s+required\\s+pam_tally2.so" < "/etc/pam.d/common-auth" &&
grep -E "^\\s*auth\\s+required\\s+pam_tally2.so" < "/etc/pam.d/common-auth" | grep -q -E -v "\\sonerr(=|\\s|\$)" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*auth\\s+required\\s+pam_tally2.so[^\\n]*)/\\1 onerr${defaultValue}/" "/etc/pam.d/common-auth"
# add a new entry if none exists
elif ! grep -q -P "^\\s*auth\\s+required\\s+pam_tally2.so(\\s.+)?\\s+onerr${valueRegex}(\\s|\$)" < "/etc/pam.d/common-auth" ; then
echo "auth required pam_tally2.so onerr${defaultValue}" >> "/etc/pam.d/common-auth"
fi
else
echo "/etc/pam.d/common-auth doesn't exist" >&2
fi
if [ -e "/etc/pam.d/common-account" ] ; then
valueRegex="" defaultValue=""
# non-empty values need to be preceded by an equals sign
[ -n "${valueRegex}" ] && valueRegex="=${valueRegex}"
# add an equals sign to non-empty values
[ -n "${defaultValue}" ] && defaultValue="=${defaultValue}"
# fix 'type' if it's wrong
if grep -q -P "^\\s*(?"'!'"account\\s)[[:alnum:]]+\\s+[[:alnum:]]+\\s+pam_tally2.so" < "/etc/pam.d/common-account" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*)[[:alnum:]]+(\\s+[[:alnum:]]+\\s+pam_tally2.so)/\\1account\\2/" "/etc/pam.d/common-account"
fi
# fix 'control' if it's wrong
if grep -q -P "^\\s*account\\s+(?"'!'"required)[[:alnum:]]+\\s+pam_tally2.so" < "/etc/pam.d/common-account" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*account\\s+)[[:alnum:]]+(\\s+pam_tally2.so)/\\1required\\2/" "/etc/pam.d/common-account"
fi
# fix the value for 'option' if one exists but does not match 'valueRegex'
if grep -q -P "^\\s*account\\s+required\\s+pam_tally2.so(\\s.+)?\\s+(?"'!'"${valueRegex}(\\s|\$))" < "/etc/pam.d/common-account" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*account\\s+required\\s+pam_tally2.so(\\s.+)?\\s)=[^[:space:]]*/\\1${defaultValue}/" "/etc/pam.d/common-account"
# add 'option=default' if option is not set
elif grep -q -E "^\\s*account\\s+required\\s+pam_tally2.so" < "/etc/pam.d/common-account" &&
grep -E "^\\s*account\\s+required\\s+pam_tally2.so" < "/etc/pam.d/common-account" | grep -q -E -v "\\s(=|\\s|\$)" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*account\\s+required\\s+pam_tally2.so[^\\n]*)/\\1 ${defaultValue}/" "/etc/pam.d/common-account"
# add a new entry if none exists
elif ! grep -q -P "^\\s*account\\s+required\\s+pam_tally2.so(\\s.+)?\\s+${valueRegex}(\\s|\$)" < "/etc/pam.d/common-account" ; then
echo "account required pam_tally2.so ${defaultValue}" >> "/etc/pam.d/common-account"
fi
else
echo "/etc/pam.d/common-account doesn't exist" >&2
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | configure |
---|
- name: Check to see if pam_tally2.so is configured in /etc/pam.d/common-auth
shell: grep -e '^\s*auth\s\+required\s\+pam_tally2\.so' /etc/pam.d/common-auth ||
true
register: check_pam_tally2_result
tags:
- CCE-85554-4
- DISA-STIG-SLES-15-020010
- accounts_passwords_pam_tally2
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Configure pam_tally2.so module in /etc/pam.d/common-auth
lineinfile:
path: /etc/pam.d/common-auth
line: auth required pam_tally2.so
state: present
when: '"pam_tally2" not in check_pam_tally2_result.stdout'
tags:
- CCE-85554-4
- DISA-STIG-SLES-15-020010
- accounts_passwords_pam_tally2
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Check to see if 'onerr' parameter is present
shell: grep -e '^\s*auth\s\+required\s\+pam_tally2\.so.*\sonerr=.*' /etc/pam.d/common-auth
|| true
register: check_onerr_result
tags:
- CCE-85554-4
- DISA-STIG-SLES-15-020010
- accounts_passwords_pam_tally2
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Make sure pam_tally2.so has 'onerr' parameter set 'fail'
replace:
path: /etc/pam.d/common-auth
regexp: ^(\s*auth\s+required\s+pam_tally2\.so\s+[^\n]*)(onerr=[A-Za-z]+)([^A-Za-z]?.*)
replace: \1onerr=fail\3
register: onerr_update_result
when: '"onerr=" in check_onerr_result.stdout'
tags:
- CCE-85554-4
- DISA-STIG-SLES-15-020010
- accounts_passwords_pam_tally2
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Add 'onerr' parameter for pam_tally2.so module in /etc/pam.d/common-auth
lineinfile:
path: /etc/pam.d/common-auth
regexp: ^(\s*auth\s+required\s+pam_tally2\.so)((\s+\S+)*\s*(\\)*$)
line: \1 onerr=fail\2
backrefs: true
state: present
when: '"onerr=" not in check_onerr_result.stdout'
tags:
- CCE-85554-4
- DISA-STIG-SLES-15-020010
- accounts_passwords_pam_tally2
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Check to see if 'deny' parameter is present
shell: grep -e '^\s*auth\s\+required\s\+pam_tally2\.so.*\sdeny=.*' /etc/pam.d/common-auth
|| true
register: check_deny_result
tags:
- CCE-85554-4
- DISA-STIG-SLES-15-020010
- accounts_passwords_pam_tally2
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Make sure pam_tally2.so has 'deny' parameter set to less than 4
replace:
path: /etc/pam.d/common-auth
regexp: ^(\s*auth\s+required\s+pam_tally2\.so\s+[^\n]*)deny=([4-9]|[1-9][0-9]+)(\s*.*)
replace: \1deny=3\3
when: '"deny=" in check_deny_result.stdout'
tags:
- CCE-85554-4
- DISA-STIG-SLES-15-020010
- accounts_passwords_pam_tally2
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Add 'deny' parameter for pam_tally2.so module in /etc/pam.d/common-auth
lineinfile:
path: /etc/pam.d/common-auth
regexp: ^(\s*auth\s+required\s+pam_tally2\.so)((\s+\S+)*\s*(\\)*$)
line: \1 deny=3\2
backrefs: true
state: present
when: '"deny=" not in check_deny_result.stdout'
tags:
- CCE-85554-4
- DISA-STIG-SLES-15-020010
- accounts_passwords_pam_tally2
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Check to see if pam_tally2.so is configured in /etc/pam.d/common-account
shell: grep -e '^\s*account\s\+required\s\+pam_tally2\.so' /etc/pam.d/common-account
|| true
register: check_account_pam_tally2_result
tags:
- CCE-85554-4
- DISA-STIG-SLES-15-020010
- accounts_passwords_pam_tally2
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Configure pam_tally2.so module in /etc/pam.d/common-account
lineinfile:
path: /etc/pam.d/common-account
line: account required pam_tally2.so
state: present
when: '"pam_tally2" not in check_account_pam_tally2_result.stdout'
tags:
- CCE-85554-4
- DISA-STIG-SLES-15-020010
- accounts_passwords_pam_tally2
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
|
Set Password Quality Requirements
[ref]groupThe default pam_pwquality PAM module provides strength
checking for passwords. It performs a number of checks, such as
making sure passwords are not similar to dictionary words, are of
at least a certain length, are not the previous password reversed,
and are not simply a change of case from the previous password. It
can also require passwords to be in certain character classes. The
pam_pwquality module is the preferred way of configuring
password requirements.
The man pages pam_pwquality(8)
provide information on the capabilities and configuration of
each. |
contains 6 rules |
Set Password Quality Requirements, if using
pam_cracklib
[ref]groupThe pam_cracklib PAM module can be configured to meet
requirements for a variety of policies.
For example, to configure pam_cracklib to require at least one uppercase
character, lowercase character, digit, and other (special)
character, locate the following line in /etc/pam.d/system-auth :
password requisite pam_cracklib.so try_first_pass retry=3
and then alter it to read:
password required pam_cracklib.so try_first_pass retry=3 maxrepeat=3 minlen=14 dcredit=-1 ucredit=-1 ocredit=-1 lcredit=-1 difok=4
If no such line exists, add one as the first line of the password section in /etc/pam.d/system-auth .
The arguments can be modified to ensure compliance with
your organization's security policy. Discussion of each parameter follows.Warning:
Note that the password quality requirements are not enforced for the
root account for some reason. |
contains 6 rules |
Set Password Strength Minimum Digit Characters
[ref]ruleThe pam_cracklib module's dcredit parameter controls requirements
for usage of digits in a password. When set to a negative number, any
password will be required to contain that many digits. When set to a
positive number, pam_cracklib will grant +1 additional length credit for
each digit. Add dcredit=-1 after pam_cracklib.so to require use of
a digit in passwords. Rationale:Requiring digits makes password guessing attacks more difficult by ensuring
a larger search space. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_password_pam_dcredit # promote to variable
set_fact:
var_password_pam_dcredit: !!str -1
tags:
- always
- name: Set control_flag fact
set_fact:
control_flag: requisite
tags:
- CCE-85564-3
- DISA-STIG-SLES-15-020150
- cracklib_accounts_password_pam_dcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check to see if 'pam_cracklib.so' module is configured in '/etc/pam.d/common-password'
shell: |
set -o pipefail
grep -E '^\s*password\s+\S+\s+pam_cracklib.so' /etc/pam.d/common-password || true
register: check_pam_module_result
tags:
- CCE-85564-3
- DISA-STIG-SLES-15-020150
- cracklib_accounts_password_pam_dcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Configure 'pam_cracklib.so' module in '/etc/pam.d/common-password'
lineinfile:
path: /etc/pam.d/common-password
line: password requisite pam_cracklib.so
state: present
when: '"pam_cracklib.so" not in check_pam_module_result.stdout'
tags:
- CCE-85564-3
- DISA-STIG-SLES-15-020150
- cracklib_accounts_password_pam_dcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure 'pam_cracklib.so' module has conforming control flag
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+)\S+(\s+pam_cracklib.so\s+.*)
line: \g<1>requisite\g<2>
backrefs: true
when: control_flag|length
tags:
- CCE-85564-3
- DISA-STIG-SLES-15-020150
- cracklib_accounts_password_pam_dcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure "pam_cracklib.so" module has argument "dcredit={{ var_password_pam_dcredit
}}"
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+requisite\s+pam_cracklib.so(?:\s+\S+)*\s+dcredit=)(?:\S+)((\s+\S+)*\s*\\*\s*)$
line: \g<1>{{ var_password_pam_dcredit }}\g<2>
backrefs: true
tags:
- CCE-85564-3
- DISA-STIG-SLES-15-020150
- cracklib_accounts_password_pam_dcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check the presence of "dcredit" argument in "pam_cracklib.so" module
shell: |
set -o pipefail
grep -E '^\s*password\s+requisite\s+pam_cracklib.so.*\s+dcredit(=|\s|\s*$)' /etc/pam.d/common-password || true
register: check_pam_module_argument_result
tags:
- CCE-85564-3
- DISA-STIG-SLES-15-020150
- cracklib_accounts_password_pam_dcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add "dcredit" argument to "pam_cracklib.so" module
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+requisite\s+pam_cracklib.so)((\s+\S+)*\s*(\\)*$)
line: \g<1> dcredit={{ var_password_pam_dcredit }}\g<2>
backrefs: true
when: '"dcredit" not in check_pam_module_argument_result.stdout'
tags:
- CCE-85564-3
- DISA-STIG-SLES-15-020150
- cracklib_accounts_password_pam_dcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Set Password Strength Minimum Different Characters
[ref]ruleThe pam_cracklib module's difok parameter controls requirements for
usage of different characters during a password change. The number of
changed characters refers to the number of changes required with respect to
the total number of positions in the current password. In other words,
characters may be the same within the two passwords; however, the positions
of the like characters must be different.
Make sure the difok parameter for the pam_cracklib module is
configured to greater than or equal to 8 . Rationale:Requiring a minimum number of different characters during password changes
ensures that newly changed passwords should not resemble previously
compromised ones. Note that passwords which are changed on compromised
systems will still be compromised, however. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_password_pam_difok # promote to variable
set_fact:
var_password_pam_difok: !!str 8
tags:
- always
- name: Set control_flag fact
set_fact:
control_flag: requisite
tags:
- CCE-85677-3
- DISA-STIG-SLES-15-020160
- NIST-800-53-IA-5(1)(b)
- NIST-800-53-IA-5(1).1(v)
- cracklib_accounts_password_pam_difok
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check to see if 'pam_cracklib.so' module is configured in '/etc/pam.d/common-password'
shell: |
set -o pipefail
grep -E '^\s*password\s+\S+\s+pam_cracklib.so' /etc/pam.d/common-password || true
register: check_pam_module_result
tags:
- CCE-85677-3
- DISA-STIG-SLES-15-020160
- NIST-800-53-IA-5(1)(b)
- NIST-800-53-IA-5(1).1(v)
- cracklib_accounts_password_pam_difok
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Configure 'pam_cracklib.so' module in '/etc/pam.d/common-password'
lineinfile:
path: /etc/pam.d/common-password
line: password requisite pam_cracklib.so
state: present
when: '"pam_cracklib.so" not in check_pam_module_result.stdout'
tags:
- CCE-85677-3
- DISA-STIG-SLES-15-020160
- NIST-800-53-IA-5(1)(b)
- NIST-800-53-IA-5(1).1(v)
- cracklib_accounts_password_pam_difok
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure 'pam_cracklib.so' module has conforming control flag
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+)\S+(\s+pam_cracklib.so\s+.*)
line: \g<1>requisite\g<2>
backrefs: true
when: control_flag|length
tags:
- CCE-85677-3
- DISA-STIG-SLES-15-020160
- NIST-800-53-IA-5(1)(b)
- NIST-800-53-IA-5(1).1(v)
- cracklib_accounts_password_pam_difok
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure "pam_cracklib.so" module has argument "difok={{ var_password_pam_difok
}}"
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+requisite\s+pam_cracklib.so(?:\s+\S+)*\s+difok=)(?:\S+)((\s+\S+)*\s*\\*\s*)$
line: \g<1>{{ var_password_pam_difok }}\g<2>
backrefs: true
tags:
- CCE-85677-3
- DISA-STIG-SLES-15-020160
- NIST-800-53-IA-5(1)(b)
- NIST-800-53-IA-5(1).1(v)
- cracklib_accounts_password_pam_difok
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check the presence of "difok" argument in "pam_cracklib.so" module
shell: |
set -o pipefail
grep -E '^\s*password\s+requisite\s+pam_cracklib.so.*\s+difok(=|\s|\s*$)' /etc/pam.d/common-password || true
register: check_pam_module_argument_result
tags:
- CCE-85677-3
- DISA-STIG-SLES-15-020160
- NIST-800-53-IA-5(1)(b)
- NIST-800-53-IA-5(1).1(v)
- cracklib_accounts_password_pam_difok
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add "difok" argument to "pam_cracklib.so" module
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+requisite\s+pam_cracklib.so)((\s+\S+)*\s*(\\)*$)
line: \g<1> difok={{ var_password_pam_difok }}\g<2>
backrefs: true
when: '"difok" not in check_pam_module_argument_result.stdout'
tags:
- CCE-85677-3
- DISA-STIG-SLES-15-020160
- NIST-800-53-IA-5(1)(b)
- NIST-800-53-IA-5(1).1(v)
- cracklib_accounts_password_pam_difok
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Set Password Strength Minimum Lowercase Characters
[ref]ruleThe pam_cracklib module's lcredit= parameter controls requirements
for usage of lowercase letters in a password. When set to a negative
number, any password will be required to contain that many lowercase
characters. When set to a positive number, pam_cracklib will grant +1
additional length credit for each lowercase character.
Add lcredit=-1 after pam_cracklib.so to require use of a
lowercase character in passwords. Rationale:Requiring a minimum number of lowercase characters makes password guessing
attacks more difficult by ensuring a larger search space. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_password_pam_lcredit # promote to variable
set_fact:
var_password_pam_lcredit: !!str -1
tags:
- always
- name: Set control_flag fact
set_fact:
control_flag: requisite
tags:
- CCE-85676-5
- DISA-STIG-SLES-15-020140
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(1).1(v)
- cracklib_accounts_password_pam_lcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check to see if 'pam_cracklib.so' module is configured in '/etc/pam.d/common-password'
shell: |
set -o pipefail
grep -E '^\s*password\s+\S+\s+pam_cracklib.so' /etc/pam.d/common-password || true
register: check_pam_module_result
tags:
- CCE-85676-5
- DISA-STIG-SLES-15-020140
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(1).1(v)
- cracklib_accounts_password_pam_lcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Configure 'pam_cracklib.so' module in '/etc/pam.d/common-password'
lineinfile:
path: /etc/pam.d/common-password
line: password requisite pam_cracklib.so
state: present
when: '"pam_cracklib.so" not in check_pam_module_result.stdout'
tags:
- CCE-85676-5
- DISA-STIG-SLES-15-020140
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(1).1(v)
- cracklib_accounts_password_pam_lcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure 'pam_cracklib.so' module has conforming control flag
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+)\S+(\s+pam_cracklib.so\s+.*)
line: \g<1>requisite\g<2>
backrefs: true
when: control_flag|length
tags:
- CCE-85676-5
- DISA-STIG-SLES-15-020140
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(1).1(v)
- cracklib_accounts_password_pam_lcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure "pam_cracklib.so" module has argument "lcredit={{ var_password_pam_lcredit
}}"
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+requisite\s+pam_cracklib.so(?:\s+\S+)*\s+lcredit=)(?:\S+)((\s+\S+)*\s*\\*\s*)$
line: \g<1>{{ var_password_pam_lcredit }}\g<2>
backrefs: true
tags:
- CCE-85676-5
- DISA-STIG-SLES-15-020140
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(1).1(v)
- cracklib_accounts_password_pam_lcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check the presence of "lcredit" argument in "pam_cracklib.so" module
shell: |
set -o pipefail
grep -E '^\s*password\s+requisite\s+pam_cracklib.so.*\s+lcredit(=|\s|\s*$)' /etc/pam.d/common-password || true
register: check_pam_module_argument_result
tags:
- CCE-85676-5
- DISA-STIG-SLES-15-020140
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(1).1(v)
- cracklib_accounts_password_pam_lcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add "lcredit" argument to "pam_cracklib.so" module
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+requisite\s+pam_cracklib.so)((\s+\S+)*\s*(\\)*$)
line: \g<1> lcredit={{ var_password_pam_lcredit }}\g<2>
backrefs: true
when: '"lcredit" not in check_pam_module_argument_result.stdout'
tags:
- CCE-85676-5
- DISA-STIG-SLES-15-020140
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(1).1(v)
- cracklib_accounts_password_pam_lcredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Set Password Minimum Length
[ref]ruleThe pam_cracklib module's minlen parameter controls requirements for
minimum characters required in a password. Add minlen=15
to set minimum password length requirements. Rationale:Password length is one factor of several that helps to determine
strength and how long it takes to crack a password. Use of more characters in
a password helps to exponentially increase the time and/or resources
required to compromise the password. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_password_pam_minlen # promote to variable
set_fact:
var_password_pam_minlen: !!str 15
tags:
- always
- name: Set control_flag fact
set_fact:
control_flag: requisite
tags:
- CCE-85573-4
- DISA-STIG-SLES-15-020260
- cracklib_accounts_password_pam_minlen
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check to see if 'pam_cracklib.so' module is configured in '/etc/pam.d/common-password'
shell: |
set -o pipefail
grep -E '^\s*password\s+\S+\s+pam_cracklib.so' /etc/pam.d/common-password || true
register: check_pam_module_result
tags:
- CCE-85573-4
- DISA-STIG-SLES-15-020260
- cracklib_accounts_password_pam_minlen
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Configure 'pam_cracklib.so' module in '/etc/pam.d/common-password'
lineinfile:
path: /etc/pam.d/common-password
line: password requisite pam_cracklib.so
state: present
when: '"pam_cracklib.so" not in check_pam_module_result.stdout'
tags:
- CCE-85573-4
- DISA-STIG-SLES-15-020260
- cracklib_accounts_password_pam_minlen
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure 'pam_cracklib.so' module has conforming control flag
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+)\S+(\s+pam_cracklib.so\s+.*)
line: \g<1>requisite\g<2>
backrefs: true
when: control_flag|length
tags:
- CCE-85573-4
- DISA-STIG-SLES-15-020260
- cracklib_accounts_password_pam_minlen
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure "pam_cracklib.so" module has argument "minlen={{ var_password_pam_minlen
}}"
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+requisite\s+pam_cracklib.so(?:\s+\S+)*\s+minlen=)(?:\S+)((\s+\S+)*\s*\\*\s*)$
line: \g<1>{{ var_password_pam_minlen }}\g<2>
backrefs: true
tags:
- CCE-85573-4
- DISA-STIG-SLES-15-020260
- cracklib_accounts_password_pam_minlen
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check the presence of "minlen" argument in "pam_cracklib.so" module
shell: |
set -o pipefail
grep -E '^\s*password\s+requisite\s+pam_cracklib.so.*\s+minlen(=|\s|\s*$)' /etc/pam.d/common-password || true
register: check_pam_module_argument_result
tags:
- CCE-85573-4
- DISA-STIG-SLES-15-020260
- cracklib_accounts_password_pam_minlen
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add "minlen" argument to "pam_cracklib.so" module
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+requisite\s+pam_cracklib.so)((\s+\S+)*\s*(\\)*$)
line: \g<1> minlen={{ var_password_pam_minlen }}\g<2>
backrefs: true
when: '"minlen" not in check_pam_module_argument_result.stdout'
tags:
- CCE-85573-4
- DISA-STIG-SLES-15-020260
- cracklib_accounts_password_pam_minlen
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Set Password Strength Minimum Special Characters
[ref]ruleThe pam_cracklib module's ocredit= parameter controls requirements
for usage of special (or ``other'') characters in a password. When set to a
negative number, any password will be required to contain that many special
characters. When set to a positive number, pam_cracklib will grant +1
additional length credit for each special character.
Make sure the ocredit parameter for the pam_cracklib module is
set to less than or equal to -1 . For example, ocredit=-1 . Rationale:Requiring a minimum number of special characters makes password guessing
attacks more difficult by ensuring a larger search space. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_password_pam_ocredit # promote to variable
set_fact:
var_password_pam_ocredit: !!str -1
tags:
- always
- name: Set control_flag fact
set_fact:
control_flag: requisite
tags:
- CCE-85574-2
- DISA-STIG-SLES-15-020270
- NIST-800-53-IA-5(a)
- NIST-800-53-IA-5(v)
- cracklib_accounts_password_pam_ocredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check to see if 'pam_cracklib.so' module is configured in '/etc/pam.d/common-password'
shell: |
set -o pipefail
grep -E '^\s*password\s+\S+\s+pam_cracklib.so' /etc/pam.d/common-password || true
register: check_pam_module_result
tags:
- CCE-85574-2
- DISA-STIG-SLES-15-020270
- NIST-800-53-IA-5(a)
- NIST-800-53-IA-5(v)
- cracklib_accounts_password_pam_ocredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Configure 'pam_cracklib.so' module in '/etc/pam.d/common-password'
lineinfile:
path: /etc/pam.d/common-password
line: password requisite pam_cracklib.so
state: present
when: '"pam_cracklib.so" not in check_pam_module_result.stdout'
tags:
- CCE-85574-2
- DISA-STIG-SLES-15-020270
- NIST-800-53-IA-5(a)
- NIST-800-53-IA-5(v)
- cracklib_accounts_password_pam_ocredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure 'pam_cracklib.so' module has conforming control flag
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+)\S+(\s+pam_cracklib.so\s+.*)
line: \g<1>requisite\g<2>
backrefs: true
when: control_flag|length
tags:
- CCE-85574-2
- DISA-STIG-SLES-15-020270
- NIST-800-53-IA-5(a)
- NIST-800-53-IA-5(v)
- cracklib_accounts_password_pam_ocredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure "pam_cracklib.so" module has argument "ocredit={{ var_password_pam_ocredit
}}"
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+requisite\s+pam_cracklib.so(?:\s+\S+)*\s+ocredit=)(?:\S+)((\s+\S+)*\s*\\*\s*)$
line: \g<1>{{ var_password_pam_ocredit }}\g<2>
backrefs: true
tags:
- CCE-85574-2
- DISA-STIG-SLES-15-020270
- NIST-800-53-IA-5(a)
- NIST-800-53-IA-5(v)
- cracklib_accounts_password_pam_ocredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check the presence of "ocredit" argument in "pam_cracklib.so" module
shell: |
set -o pipefail
grep -E '^\s*password\s+requisite\s+pam_cracklib.so.*\s+ocredit(=|\s|\s*$)' /etc/pam.d/common-password || true
register: check_pam_module_argument_result
tags:
- CCE-85574-2
- DISA-STIG-SLES-15-020270
- NIST-800-53-IA-5(a)
- NIST-800-53-IA-5(v)
- cracklib_accounts_password_pam_ocredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add "ocredit" argument to "pam_cracklib.so" module
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+requisite\s+pam_cracklib.so)((\s+\S+)*\s*(\\)*$)
line: \g<1> ocredit={{ var_password_pam_ocredit }}\g<2>
backrefs: true
when: '"ocredit" not in check_pam_module_argument_result.stdout'
tags:
- CCE-85574-2
- DISA-STIG-SLES-15-020270
- NIST-800-53-IA-5(a)
- NIST-800-53-IA-5(v)
- cracklib_accounts_password_pam_ocredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Set Password Strength Minimum Uppercase Characters
[ref]ruleThe pam_cracklib module's ucredit= parameter controls requirements
for usage of uppercase letters in a password. When set to a negative
number, any password will be required to contain that many uppercase
characters. When set to a positive number, pam_cracklib will grant +1
additional length credit for each uppercase character.
Add ucredit=-1 after pam_cracklib.so to require use of an upper
case character in passwords. Rationale:Requiring a minimum number of uppercase characters makes password guessing
attacks more difficult by ensuring a larger search space. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_password_pam_ucredit # promote to variable
set_fact:
var_password_pam_ucredit: !!str -1
tags:
- always
- name: Set control_flag fact
set_fact:
control_flag: requisite
tags:
- CCE-85675-7
- DISA-STIG-SLES-15-020130
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(1).1(v)
- cracklib_accounts_password_pam_ucredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check to see if 'pam_cracklib.so' module is configured in '/etc/pam.d/common-password'
shell: |
set -o pipefail
grep -E '^\s*password\s+\S+\s+pam_cracklib.so' /etc/pam.d/common-password || true
register: check_pam_module_result
tags:
- CCE-85675-7
- DISA-STIG-SLES-15-020130
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(1).1(v)
- cracklib_accounts_password_pam_ucredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Configure 'pam_cracklib.so' module in '/etc/pam.d/common-password'
lineinfile:
path: /etc/pam.d/common-password
line: password requisite pam_cracklib.so
state: present
when: '"pam_cracklib.so" not in check_pam_module_result.stdout'
tags:
- CCE-85675-7
- DISA-STIG-SLES-15-020130
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(1).1(v)
- cracklib_accounts_password_pam_ucredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure 'pam_cracklib.so' module has conforming control flag
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+)\S+(\s+pam_cracklib.so\s+.*)
line: \g<1>requisite\g<2>
backrefs: true
when: control_flag|length
tags:
- CCE-85675-7
- DISA-STIG-SLES-15-020130
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(1).1(v)
- cracklib_accounts_password_pam_ucredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure "pam_cracklib.so" module has argument "ucredit={{ var_password_pam_ucredit
}}"
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+requisite\s+pam_cracklib.so(?:\s+\S+)*\s+ucredit=)(?:\S+)((\s+\S+)*\s*\\*\s*)$
line: \g<1>{{ var_password_pam_ucredit }}\g<2>
backrefs: true
tags:
- CCE-85675-7
- DISA-STIG-SLES-15-020130
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(1).1(v)
- cracklib_accounts_password_pam_ucredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check the presence of "ucredit" argument in "pam_cracklib.so" module
shell: |
set -o pipefail
grep -E '^\s*password\s+requisite\s+pam_cracklib.so.*\s+ucredit(=|\s|\s*$)' /etc/pam.d/common-password || true
register: check_pam_module_argument_result
tags:
- CCE-85675-7
- DISA-STIG-SLES-15-020130
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(1).1(v)
- cracklib_accounts_password_pam_ucredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add "ucredit" argument to "pam_cracklib.so" module
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+requisite\s+pam_cracklib.so)((\s+\S+)*\s*(\\)*$)
line: \g<1> ucredit={{ var_password_pam_ucredit }}\g<2>
backrefs: true
when: '"ucredit" not in check_pam_module_argument_result.stdout'
tags:
- CCE-85675-7
- DISA-STIG-SLES-15-020130
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(1).1(v)
- cracklib_accounts_password_pam_ucredit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Set Password Hashing Algorithm
[ref]groupThe system's default algorithm for storing password hashes in
/etc/shadow is SHA-512. This can be configured in several
locations. |
contains 4 rules |
Set PAM's Common Authentication Hashing Algorithm
[ref]ruleThe PAM system service can be configured to only store encrypted
representations of passwords. In
/etc/pam.d/common-auth ,
the
auth section of the file controls which PAM modules execute
during a password change. Set the pam_unix.so module in the
auth section to include the argument sha512 , as shown
below:
auth required pam_unix.so sha512 other arguments...
This will help ensure when local users change their authentication method,
hashes for the new authentications will be generated using the SHA-512
algorithm. This is the default.Rationale:Unapproved mechanisms used for authentication to the cryptographic module
are not verified and therefore cannot be relied on to provide
confidentiality or integrity, and data may be compromised.
This setting ensures user and group account administration utilities are
configured to store only encrypted representations of passwords.
Additionally, the crypt_style configuration option ensures the use
of a strong hashing algorithm that makes password cracking attacks more
difficult. Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
if [ -e "/etc/pam.d/common-auth" ] ; then
valueRegex="" defaultValue=""
# non-empty values need to be preceded by an equals sign
[ -n "${valueRegex}" ] && valueRegex="=${valueRegex}"
# add an equals sign to non-empty values
[ -n "${defaultValue}" ] && defaultValue="=${defaultValue}"
# fix 'type' if it's wrong
if grep -q -P "^\\s*(?"'!'"auth\\s)[[:alnum:]]+\\s+[[:alnum:]]+\\s+pam_unix.so" < "/etc/pam.d/common-auth" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*)[[:alnum:]]+(\\s+[[:alnum:]]+\\s+pam_unix.so)/\\1auth\\2/" "/etc/pam.d/common-auth"
fi
# fix 'control' if it's wrong
if grep -q -P "^\\s*auth\\s+(?"'!'"required)[[:alnum:]]+\\s+pam_unix.so" < "/etc/pam.d/common-auth" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*auth\\s+)[[:alnum:]]+(\\s+pam_unix.so)/\\1required\\2/" "/etc/pam.d/common-auth"
fi
# fix the value for 'option' if one exists but does not match 'valueRegex'
if grep -q -P "^\\s*auth\\s+required\\s+pam_unix.so(\\s.+)?\\s+sha512(?"'!'"${valueRegex}(\\s|\$))" < "/etc/pam.d/common-auth" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*auth\\s+required\\s+pam_unix.so(\\s.+)?\\s)sha512=[^[:space:]]*/\\1sha512${defaultValue}/" "/etc/pam.d/common-auth"
# add 'option=default' if option is not set
elif grep -q -E "^\\s*auth\\s+required\\s+pam_unix.so" < "/etc/pam.d/common-auth" &&
grep -E "^\\s*auth\\s+required\\s+pam_unix.so" < "/etc/pam.d/common-auth" | grep -q -E -v "\\ssha512(=|\\s|\$)" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*auth\\s+required\\s+pam_unix.so[^\\n]*)/\\1 sha512${defaultValue}/" "/etc/pam.d/common-auth"
# add a new entry if none exists
elif ! grep -q -P "^\\s*auth\\s+required\\s+pam_unix.so(\\s.+)?\\s+sha512${valueRegex}(\\s|\$)" < "/etc/pam.d/common-auth" ; then
echo "auth required pam_unix.so sha512${defaultValue}" >> "/etc/pam.d/common-auth"
fi
else
echo "/etc/pam.d/common-auth doesn't exist" >&2
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85754-0
- DISA-STIG-SLES-15-010250
- NIST-800-53-IA-7
- NIST-800-53-IA-7.1
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_commonauth
- name: Set control_flag fact
set_fact:
control_flag: required
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85754-0
- DISA-STIG-SLES-15-010250
- NIST-800-53-IA-7
- NIST-800-53-IA-7.1
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_commonauth
- name: Check to see if 'pam_unix.so' module is configured in '/etc/pam.d/common-auth'
shell: |
set -o pipefail
grep -E '^\s*auth\s+\S+\s+pam_unix.so' /etc/pam.d/common-auth || true
register: check_pam_module_result
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85754-0
- DISA-STIG-SLES-15-010250
- NIST-800-53-IA-7
- NIST-800-53-IA-7.1
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_commonauth
- name: Configure 'pam_unix.so' module in '/etc/pam.d/common-auth'
lineinfile:
path: /etc/pam.d/common-auth
line: auth required pam_unix.so
state: present
when:
- '"pam" in ansible_facts.packages'
- '"pam_unix.so" not in check_pam_module_result.stdout'
tags:
- CCE-85754-0
- DISA-STIG-SLES-15-010250
- NIST-800-53-IA-7
- NIST-800-53-IA-7.1
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_commonauth
- name: Ensure 'pam_unix.so' module has conforming control flag
lineinfile:
path: /etc/pam.d/common-auth
regexp: ^(\s*auth\s+)\S+(\s+pam_unix.so\s+.*)
line: \g<1>required\g<2>
backrefs: true
when:
- '"pam" in ansible_facts.packages'
- control_flag|length
tags:
- CCE-85754-0
- DISA-STIG-SLES-15-010250
- NIST-800-53-IA-7
- NIST-800-53-IA-7.1
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_commonauth
- name: Set argument_value fact
set_fact:
argument_value: ''
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85754-0
- DISA-STIG-SLES-15-010250
- NIST-800-53-IA-7
- NIST-800-53-IA-7.1
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_commonauth
- name: Ensure "pam_unix.so" module has argument "sha512"
lineinfile:
path: /etc/pam.d/common-auth
regexp: ^(\s*auth\s+required\s+pam_unix.so(?:\s+\S+)*\s+sha512=)(?!)\S*((\s+\S+)*\s*\\*\s*)$
line: \g<1>\g<2>
backrefs: true
when:
- '"pam" in ansible_facts.packages'
- argument_value|length
tags:
- CCE-85754-0
- DISA-STIG-SLES-15-010250
- NIST-800-53-IA-7
- NIST-800-53-IA-7.1
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_commonauth
- name: Check the presence of "sha512" argument in "pam_unix.so" module
shell: |
set -o pipefail
grep -E '^\s*auth\s+required\s+pam_unix.so.*\s+sha512(=|\s|\s*$)' /etc/pam.d/common-auth || true
register: check_pam_module_argument_result
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85754-0
- DISA-STIG-SLES-15-010250
- NIST-800-53-IA-7
- NIST-800-53-IA-7.1
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_commonauth
- name: Add "sha512" argument to "pam_unix.so" module
lineinfile:
path: /etc/pam.d/common-auth
regexp: ^(\s*auth\s+required\s+pam_unix.so)((\s+\S+)*\s*(\\)*$)
line: \g<1> sha512\g<2>
backrefs: true
when:
- '"pam" in ansible_facts.packages'
- '"sha512" not in check_pam_module_argument_result.stdout'
tags:
- CCE-85754-0
- DISA-STIG-SLES-15-010250
- NIST-800-53-IA-7
- NIST-800-53-IA-7.1
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_commonauth
|
Set Password Hashing Algorithm in /etc/login.defs
[ref]ruleIn /etc/login.defs , add or correct the following line to ensure
the system will use SHA-512 as the hashing algorithm:
ENCRYPT_METHOD SHA512 Rationale:Passwords need to be protected at all times, and encryption is the standard method for protecting passwords.
If passwords are not encrypted, they can be plainly read (i.e., clear text) and easily compromised. Passwords
that are encrypted with a weak algorithm are no more protected than if they are kept in plain text.
Using a stronger hashing algorithm makes password cracking attacks more difficult. Identifiers:
CCE-83279-0 References:
BP28(R32), 5.4.1.2, 1, 12, 15, 16, 5, 5.6.2.2, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.13.11, CCI-000196, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 0418, 1055, 1402, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(c), IA-5(1)(c), CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.2.1, SRG-OS-000073-GPOS-00041, SLES-15-010260, SV-234825r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q shadow; then
var_password_hashing_algorithm="SHA512"
if grep --silent ^ENCRYPT_METHOD /etc/login.defs ; then
sed -i "s/^ENCRYPT_METHOD .*/ENCRYPT_METHOD $var_password_hashing_algorithm/g" /etc/login.defs
else
echo "" >> /etc/login.defs
echo "ENCRYPT_METHOD $var_password_hashing_algorithm" >> /etc/login.defs
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83279-0
- CJIS-5.6.2.2
- DISA-STIG-SLES-15-010260
- NIST-800-171-3.13.11
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(c)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.1
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_logindefs
- name: XCCDF Value var_password_hashing_algorithm # promote to variable
set_fact:
var_password_hashing_algorithm: !!str SHA512
tags:
- always
- name: Set Password Hashing Algorithm in /etc/login.defs
lineinfile:
dest: /etc/login.defs
regexp: ^#?ENCRYPT_METHOD
line: ENCRYPT_METHOD {{ var_password_hashing_algorithm }}
state: present
create: true
when: '"shadow" in ansible_facts.packages'
tags:
- CCE-83279-0
- CJIS-5.6.2.2
- DISA-STIG-SLES-15-010260
- NIST-800-171-3.13.11
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(c)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.1
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_logindefs
|
Set PAM's Password Hashing Algorithm
[ref]ruleThe PAM system service can be configured to only store encrypted
representations of passwords. In
/etc/pam.d/common-password ,
the
password section of the file controls which PAM modules execute
during a password change. Set the pam_unix.so module in the
password section to include the argument sha512 , as shown
below:
password required pam_unix.so sha512 other arguments...
This will help ensure when local users change their passwords, hashes for
the new passwords will be generated using the SHA-512 algorithm. This is
the default.Rationale:Passwords need to be protected at all times, and encryption is the standard
method for protecting passwords. If passwords are not encrypted, they can
be plainly read (i.e., clear text) and easily compromised. Passwords that
are encrypted with a weak algorithm are no more protected than if they are
kepy in plain text.
This setting ensures user and group account administration utilities are
configured to store only encrypted representations of passwords.
Additionally, the crypt_style configuration option ensures the use
of a strong hashing algorithm that makes password cracking attacks more
difficult. Identifiers:
CCE-85565-0 References:
BP28(R32), 1, 12, 15, 16, 5, 5.6.2.2, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.13.11, CCI-000196, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 0418, 1055, 1402, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(c), IA-5(1)(c), CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.2.1, SRG-OS-000073-GPOS-00041, SLES-15-020170, SV-234886r622137_rule, SRG-OS-000480-VMM-002000 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
AUTH_FILES[0]="/etc/pam.d/system-auth"
AUTH_FILES[1]="/etc/pam.d/password-auth"
for pamFile in "${AUTH_FILES[@]}"
do
if ! grep -q "^password.*sufficient.*pam_unix.so.*sha512" $pamFile; then
sed -i --follow-symlinks "/^password.*sufficient.*pam_unix.so/ s/$/ sha512/" $pamFile
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85565-0
- CJIS-5.6.2.2
- DISA-STIG-SLES-15-020170
- NIST-800-171-3.13.11
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(c)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.1
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_systemauth
- name: Set control_flag fact
set_fact:
control_flag: required
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85565-0
- CJIS-5.6.2.2
- DISA-STIG-SLES-15-020170
- NIST-800-171-3.13.11
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(c)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.1
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_systemauth
- name: Check to see if 'pam_unix.so' module is configured in '/etc/pam.d/common-password'
shell: |
set -o pipefail
grep -E '^\s*password\s+\S+\s+pam_unix.so' /etc/pam.d/common-password || true
register: check_pam_module_result
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85565-0
- CJIS-5.6.2.2
- DISA-STIG-SLES-15-020170
- NIST-800-171-3.13.11
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(c)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.1
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_systemauth
- name: Configure 'pam_unix.so' module in '/etc/pam.d/common-password'
lineinfile:
path: /etc/pam.d/common-password
line: password required pam_unix.so
state: present
when:
- '"pam" in ansible_facts.packages'
- '"pam_unix.so" not in check_pam_module_result.stdout'
tags:
- CCE-85565-0
- CJIS-5.6.2.2
- DISA-STIG-SLES-15-020170
- NIST-800-171-3.13.11
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(c)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.1
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_systemauth
- name: Ensure 'pam_unix.so' module has conforming control flag
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+)\S+(\s+pam_unix.so\s+.*)
line: \g<1>required\g<2>
backrefs: true
when:
- '"pam" in ansible_facts.packages'
- control_flag|length
tags:
- CCE-85565-0
- CJIS-5.6.2.2
- DISA-STIG-SLES-15-020170
- NIST-800-171-3.13.11
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(c)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.1
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_systemauth
- name: Set argument_value fact
set_fact:
argument_value: ''
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85565-0
- CJIS-5.6.2.2
- DISA-STIG-SLES-15-020170
- NIST-800-171-3.13.11
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(c)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.1
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_systemauth
- name: Ensure "pam_unix.so" module has argument "sha512"
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+required\s+pam_unix.so(?:\s+\S+)*\s+sha512=)(?!)\S*((\s+\S+)*\s*\\*\s*)$
line: \g<1>\g<2>
backrefs: true
when:
- '"pam" in ansible_facts.packages'
- argument_value|length
tags:
- CCE-85565-0
- CJIS-5.6.2.2
- DISA-STIG-SLES-15-020170
- NIST-800-171-3.13.11
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(c)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.1
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_systemauth
- name: Check the presence of "sha512" argument in "pam_unix.so" module
shell: |
set -o pipefail
grep -E '^\s*password\s+required\s+pam_unix.so.*\s+sha512(=|\s|\s*$)' /etc/pam.d/common-password || true
register: check_pam_module_argument_result
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85565-0
- CJIS-5.6.2.2
- DISA-STIG-SLES-15-020170
- NIST-800-171-3.13.11
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(c)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.1
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_systemauth
- name: Add "sha512" argument to "pam_unix.so" module
lineinfile:
path: /etc/pam.d/common-password
regexp: ^(\s*password\s+required\s+pam_unix.so)((\s+\S+)*\s*(\\)*$)
line: \g<1> sha512\g<2>
backrefs: true
when:
- '"pam" in ansible_facts.packages'
- '"sha512" not in check_pam_module_argument_result.stdout'
tags:
- CCE-85565-0
- CJIS-5.6.2.2
- DISA-STIG-SLES-15-020170
- NIST-800-171-3.13.11
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(c)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.1
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_algorithm_systemauth
|
Set Password Hashing Rounds in /etc/login.defs
[ref]ruleIn /etc/login.defs , ensure SHA_CRYPT_MIN_ROUNDS and
SHA_CRYPT_MAX_ROUNDS has the minimum value of 5000 .
For example:
SHA_CRYPT_MIN_ROUNDS 5000
SHA_CRYPT_MAX_ROUNDS 5000
Notice that if neither are set, they already have the default value of 5000.
If either is set, they must have the minimum value of 5000.Rationale:Passwords need to be protected at all times, and encryption is the standard
method for protecting passwords. If passwords are not encrypted, they can
be plainly read (i.e., clear text) and easily compromised. Passwords
that are encrypted with a weak algorithm are no more protected than if
they are kept in plain text.
Using more hashing rounds makes password cracking attacks more difficult. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Ensure SHA_CRYPT_MIN_ROUNDS has minimum value of 5000
replace:
path: /etc/login.defs
regexp: (^\s*SHA_CRYPT_MIN_ROUNDS\s+)(?!(?:[5-9]\d{3,}|\d{5,}))\S*(\s*$)
replace: \g<1>5000\g<2>
backup: false
tags:
- CCE-85567-6
- DISA-STIG-SLES-15-020180
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_min_rounds_logindefs
- name: Check to see if SHA_CRYPT_MIN_ROUNDS is explicitly configured
shell: |
set -o pipefail
grep -e '^\s*SHA_CRYPT_MIN_ROUNDS\s\+' /etc/login.defs || true
register: check_sha_crypt_min_rounds_result
tags:
- CCE-85567-6
- DISA-STIG-SLES-15-020180
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_min_rounds_logindefs
- name: Ensure SHA_CRYPT_MAX_ROUNDS has minimum value of 5000
replace:
path: /etc/login.defs
regexp: (^\s*SHA_CRYPT_MAX_ROUNDS\s+)(?!(?:[5-9]\d{3,}|\d{5,}))\S*(\s*$)
replace: \g<1>5000\g<2>
backup: false
when: '"SHA_CRYPT_MIN_ROUNDS" not in check_sha_crypt_min_rounds_result.stdout'
tags:
- CCE-85567-6
- DISA-STIG-SLES-15-020180
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- set_password_hashing_min_rounds_logindefs
|
Ensure PAM Displays Last Logon/Access Notification
[ref]ruleTo configure the system to notify users of last logon/access
using pam_lastlog , add or correct the pam_lastlog
settings in
/etc/pam.d/login to read as follows:
session required pam_lastlog.so showfailed
And make sure that the silent option is not set.Rationale:Users need to be aware of activity that occurs regarding
their account. Providing users with information regarding the number
of unsuccessful attempts that were made to login to their account
allows the user to determine if any unauthorized activity has occurred
and gives them an opportunity to notify administrators. Identifiers:
CCE-85560-1 References:
1, 12, 15, 16, 5.5.2, DSS05.04, DSS05.10, DSS06.10, CCI-000366, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, 0582, 0584, 05885, 0586, 0846, 0957, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, AC-9(1), CM-6(a), PR.AC-7, Req-10.2.4, SRG-OS-000480-GPOS-00227, SLES-15-020080, SV-234873r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then
if [ -e "/etc/pam.d/login" ] ; then
valueRegex="" defaultValue=""
# non-empty values need to be preceded by an equals sign
[ -n "${valueRegex}" ] && valueRegex="=${valueRegex}"
# add an equals sign to non-empty values
[ -n "${defaultValue}" ] && defaultValue="=${defaultValue}"
# fix 'type' if it's wrong
if grep -q -P "^\\s*(?"'!'"session\\s)[[:alnum:]]+\\s+[[:alnum:]]+\\s+pam_lastlog.so" < "/etc/pam.d/login" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*)[[:alnum:]]+(\\s+[[:alnum:]]+\\s+pam_lastlog.so)/\\1session\\2/" "/etc/pam.d/login"
fi
# fix 'control' if it's wrong
if grep -q -P "^\\s*session\\s+(?"'!'"required)[[:alnum:]]+\\s+pam_lastlog.so" < "/etc/pam.d/login" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*session\\s+)[[:alnum:]]+(\\s+pam_lastlog.so)/\\1required\\2/" "/etc/pam.d/login"
fi
# fix the value for 'option' if one exists but does not match 'valueRegex'
if grep -q -P "^\\s*session\\s+required\\s+pam_lastlog.so(\\s.+)?\\s+showfailed(?"'!'"${valueRegex}(\\s|\$))" < "/etc/pam.d/login" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*session\\s+required\\s+pam_lastlog.so(\\s.+)?\\s)showfailed=[^[:space:]]*/\\1showfailed${defaultValue}/" "/etc/pam.d/login"
# add 'option=default' if option is not set
elif grep -q -E "^\\s*session\\s+required\\s+pam_lastlog.so" < "/etc/pam.d/login" &&
grep -E "^\\s*session\\s+required\\s+pam_lastlog.so" < "/etc/pam.d/login" | grep -q -E -v "\\sshowfailed(=|\\s|\$)" ; then
sed --follow-symlinks -i -E -e "s/^(\\s*session\\s+required\\s+pam_lastlog.so[^\\n]*)/\\1 showfailed${defaultValue}/" "/etc/pam.d/login"
# add a new entry if none exists
elif ! grep -q -P "^\\s*session\\s+required\\s+pam_lastlog.so(\\s.+)?\\s+showfailed${valueRegex}(\\s|\$)" < "/etc/pam.d/login" ; then
echo "session required pam_lastlog.so showfailed${defaultValue}" >> "/etc/pam.d/login"
fi
else
echo "/etc/pam.d/login doesn't exist" >&2
fi
# remove 'silent' option
sed -i --follow-symlinks -E -e 's/^([^#]+pam_lastlog\.so[^#]*)\ssilent/\1/' '/etc/pam.d/login'
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85560-1
- CJIS-5.5.2
- DISA-STIG-SLES-15-020080
- NIST-800-53-AC-9(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.4
- configure_strategy
- display_login_attempts
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- name: Check if pam_lastlog.so is set
lineinfile:
path: /etc/pam.d/login
regexp: ^\s*(session)(\s+)[^\s]+(\s+)(pam_lastlog\.so)(\s+)(.*)
state: absent
check_mode: true
changed_when: false
register: pam_lastlog_exists
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85560-1
- CJIS-5.5.2
- DISA-STIG-SLES-15-020080
- NIST-800-53-AC-9(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.4
- configure_strategy
- display_login_attempts
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- name: Make sure pam_lastlog.so control is required
replace:
path: /etc/pam.d/login
regexp: ^\s*(session)(\s+)[^\s]+(\s+)(pam_lastlog\.so)(\s+)(.*)
replace: \1\2required\3\4\5\6
register: control_update_result
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85560-1
- CJIS-5.5.2
- DISA-STIG-SLES-15-020080
- NIST-800-53-AC-9(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.4
- configure_strategy
- display_login_attempts
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- name: Add control for pam_lastlog.so module
lineinfile:
path: /etc/pam.d/login
line: session required pam_lastlog.so showfailed
when:
- '"pam" in ansible_facts.packages'
- not pam_lastlog_exists.found
register: add_new_pam_lastlog_control_result
tags:
- CCE-85560-1
- CJIS-5.5.2
- DISA-STIG-SLES-15-020080
- NIST-800-53-AC-9(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.4
- configure_strategy
- display_login_attempts
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- name: Add 'showfailed' arg to pam_lastlog.so module
pamd:
name: login
type: session
control: required
module_path: pam_lastlog.so
module_arguments: showfailed
state: args_present
when:
- '"pam" in ansible_facts.packages'
- not add_new_pam_lastlog_control_result.changed
tags:
- CCE-85560-1
- CJIS-5.5.2
- DISA-STIG-SLES-15-020080
- NIST-800-53-AC-9(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.4
- configure_strategy
- display_login_attempts
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- name: Remove 'silent' arg for pam_lastlog.so module
pamd:
name: login
type: session
control: required
module_path: pam_lastlog.so
module_arguments: silent
state: args_absent
when:
- '"pam" in ansible_facts.packages'
- not add_new_pam_lastlog_control_result.changed
tags:
- CCE-85560-1
- CJIS-5.5.2
- DISA-STIG-SLES-15-020080
- NIST-800-53-AC-9(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.4
- configure_strategy
- display_login_attempts
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
|
The PAM configuration should not be changed automatically
[ref]ruleVerify the SUSE operating system is configured to not overwrite Pluggable
Authentication Modules (PAM) configuration on package changes. Rationale:pam-config is a command line utility that automatically generates
a system PAM configuration as packages are installed, updated or removed
from the system. pam-config removes configurations for PAM modules
and parameters that it does not know about. It may render ineffective PAM
configuration by the system administrator and thus impact system security. Remediation Shell script: (show)
for link in $(find /etc/pam.d/ -type l -iname "common-*") ; do
target=$(readlink -f "$link")
cp -p --remove-destination "$target" "$link"
done
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Find soft links /etc/pam.d/
find:
paths: /etc/pam.d
file_type: link
patterns: common-.*
use_regex: true
register: find_pam_soft_links_result
tags:
- CCE-85641-9
- DISA-STIG-SLES-15-040220
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- pam_disable_automatic_configuration
- restrict_strategy
- name: Remove soft links in /etc/pam.d/
shell: |
set -o pipefail
target=$(readlink -f "{{ item.path }}")
cp -p --remove-destination "$target" "{{ item.path }}"
with_items: '{{ find_pam_soft_links_result.files }}'
tags:
- CCE-85641-9
- DISA-STIG-SLES-15-040220
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- pam_disable_automatic_configuration
- restrict_strategy
|
Protect Physical Console Access
[ref]groupIt is impossible to fully protect a system from an
attacker with physical access, so securing the space in which the
system is located should be considered a necessary step. However,
there are some steps which, if taken, make it more difficult for an
attacker to quickly or undetectably modify a system from its
console. |
contains 7 rules |
Configure Screen Locking
[ref]groupWhen a user must temporarily leave an account
logged-in, screen locking should be employed to prevent passersby
from abusing the account. User education and training is
particularly important for screen locking to be effective, and policies
can be implemented to reinforce this.
Automatic screen locking is only meant as a safeguard for
those cases where a user forgot to lock the screen. |
contains 5 rules |
Configure Console Screen Locking
[ref]groupA console screen locking mechanism is a temporary action taken when a user
stops work and moves away from the immediate physical vicinity of the
information system but does not logout because of the temporary nature of
the absence. Rather than relying on the user to manually lock their
operation system session prior to vacating the vicinity, operating systems
need to be able to identify when a user's session has idled and take action
to initiate the session lock. |
contains 1 rule |
Check that vlock is installed to allow session locking
[ref]ruleThe SUSE Linux Enterprise 15 operating system must have vlock installed to allow for session locking.
The kbd package can be installed with the following command:
$ sudo zypper install kbd Rationale:A session lock is a temporary action taken when a user stops work and
moves away from the immediate physical vicinity of the information
system but does not want to log out because of the temporary nature of
the absence.
The session lock is implemented at the point where session activity can
be determined.
Regardless of where the session lock is determined and implemented,
once invoked, the session lock must remain in place until the user
reauthenticates. No other activity aside from reauthentication must
unlock the system. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
zypper install -y "kbd"
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
- name: Ensure kbd is installed
package:
name: kbd
state: present
tags:
- CCE-83268-3
- DISA-STIG-SLES-15-010110
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- vlock_installed
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include install_kbd
class install_kbd {
package { 'kbd':
ensure => 'installed',
}
}
Remediation script: (show)
[[packages]]
name = "kbd"
version = "*"
|
Hardware Tokens for Authentication
[ref]groupThe use of hardware tokens such as smart cards for system login
provides stronger, two-factor authentication than using a username and password.
In Red Hat Enterprise Linux servers and workstations, hardware token login
is not enabled by default and must be enabled in the system settings. |
contains 4 rules |
Install Smart Card Packages For Multifactor Authentication
[ref]ruleConfigure the operating system to implement multifactor authentication by
installing the required package with the following command:
The pam_pkcs11 package can be installed with the following command:
$ sudo zypper install pam_pkcs11
The mozilla-nss package can be installed with the following command:
$ sudo zypper install mozilla-nss
The mozilla-nss-tools package can be installed with the following command:
$ sudo zypper install mozilla-nss-tools
The pcsc-ccid package can be installed with the following command:
$ sudo zypper install pcsc-ccid
The pcsc-lite package can be installed with the following command:
$ sudo zypper install pcsc-lite
The pcsc-tools package can be installed with the following command:
$ sudo zypper install pcsc-tools
The opensc package can be installed with the following command:
$ sudo zypper install opensc Rationale:Using an authentication device, such as a CAC or token that is separate from
the information system, ensures that even if the information system is
compromised, that compromise will not affect credentials stored on the
authentication device.
Multifactor solutions that require devices separate from
information systems gaining access include, for example, hardware tokens
providing time-based or challenge-response authenticators and smart cards such
as the U.S. Government Personal Identity Verification card and the DoD Common
Access Card. Identifiers:
CCE-83292-3 References:
CCI-000765, CCI-001948, CCI-001953, CCI-001954, CM-6(a), SRG-OS-000105-GPOS-00052, SRG-OS-000375-GPOS-00160, SRG-OS-000375-GPOS-00161, SRG-OS-000377-GPOS-00162, SLES-15-010460, SV-234854r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
- name: Set smartcard packages fact
set_fact:
smartcard_packages:
- pam_pkcs11
- mozilla-nss
- mozilla-nss-tools
- pcsc-ccid
- pcsc-lite
- pcsc-tools
- opensc
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83292-3
- DISA-STIG-SLES-15-010460
- NIST-800-53-CM-6(a)
- enable_strategy
- install_smartcard_packages
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure {{ smartcard_packages }} are installed
package:
name: '{{ smartcard_packages }}'
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83292-3
- DISA-STIG-SLES-15-010460
- NIST-800-53-CM-6(a)
- enable_strategy
- install_smartcard_packages
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
|
Configure Smart Card Certificate Authority Validation
[ref]ruleConfigure the operating system to do certificate status checking for PKI
authentication. Modify all of the cert_policy lines in
/etc/pam_pkcs11/pam_pkcs11.conf to include ca like so:
cert_policy = ca, ocsp_on, signature; Rationale:Using an authentication device, such as a CAC or token that is separate from
the information system, ensures that even if the information system is
compromised, that compromise will not affect credentials stored on the
authentication device.
Multifactor solutions that require devices separate from
information systems gaining access include, for example, hardware tokens
providing time-based or challenge-response authenticators and smart cards such
as the U.S. Government Personal Identity Verification card and the DoD Common
Access Card. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: package facts
package_facts: null
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83272-5
- DISA-STIG-SLES-15-010170
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- smartcard_configure_ca
- name: Replace 'none' from cert_policy
replace:
path: /etc/pam_pkcs11/pam_pkcs11.conf
regexp: (^\s*cert_policy\s*=\s*)none\s*;(\s*$)
replace: \g<1>ocsp_on,ca,signature;\g<2>
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '''pam_pkcs11'' in ansible_facts.packages'
tags:
- CCE-83272-5
- DISA-STIG-SLES-15-010170
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- smartcard_configure_ca
- name: Add 'ca' parameter for cert_policy in /etc/pam_pkcs11/pam_pkcs11.conf
replace:
path: /etc/pam_pkcs11/pam_pkcs11.conf
regexp: (^\s*cert_policy\s*=\s*)(?!.*ca)(.*)
replace: \g<1>ca,\g<2>
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '''pam_pkcs11'' in ansible_facts.packages'
tags:
- CCE-83272-5
- DISA-STIG-SLES-15-010170
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- smartcard_configure_ca
|
Configure Smart Card Certificate Status Checking
[ref]ruleConfigure the operating system to do certificate status checking for PKI
authentication. Modify all of the cert_policy lines in
/etc/pam_pkcs11/pam_pkcs11.conf to include ocsp_on like so:
cert_policy = ca, ocsp_on, signature; Rationale:Using an authentication device, such as a CAC or token that is separate from
the information system, ensures that even if the information system is
compromised, that compromise will not affect credentials stored on the
authentication device.
Multifactor solutions that require devices separate from
information systems gaining access include, for example, hardware tokens
providing time-based or challenge-response authenticators and smart cards such
as the U.S. Government Personal Identity Verification card and the DoD Common
Access Card. Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Install required packages
if ! rpm --quiet -q pam_pkcs11; then yum -y -d 1 install pam_pkcs11; fi
if grep "^\s*cert_policy" /etc/pam_pkcs11/pam_pkcs11.conf | grep -qv "ocsp_on"; then
sed -i "/^\s*#/! s/cert_policy.*/cert_policy = ca, ocsp_on, signature;/g" /etc/pam_pkcs11/pam_pkcs11.conf
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: package facts
package_facts: null
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83293-1
- DISA-STIG-SLES-15-010470
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- smartcard_configure_cert_checking
- name: Replace 'none' from cert_policy
replace:
path: /etc/pam_pkcs11/pam_pkcs11.conf
regexp: (^\s*cert_policy\s*=\s*)none\s*;(\s*$)
replace: \g<1>ocsp_on,ca,signature;\g<2>
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '''pam_pkcs11'' in ansible_facts.packages'
tags:
- CCE-83293-1
- DISA-STIG-SLES-15-010470
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- smartcard_configure_cert_checking
- name: Add 'ocsp_on' parameter for cert_policy in /etc/pam_pkcs11/pam_pkcs11.conf
replace:
path: /etc/pam_pkcs11/pam_pkcs11.conf
regexp: (^\s*cert_policy\s*=\s*)(?!.*ocsp_on)(.*)
replace: \g<1>ocsp_on,\g<2>
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '''pam_pkcs11'' in ansible_facts.packages'
tags:
- CCE-83293-1
- DISA-STIG-SLES-15-010470
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- smartcard_configure_cert_checking
|
Enable Smart Card Logins in PAM
[ref]ruleThis requirement only applies to components where this is specific to the
function of the device or has the concept of an organizational user (e.g.,
VPN, proxy capability). This does not apply to authentication for the
purpose of configuring the device itself (management).
Check that the pam_pkcs11.so option is configured in the
etc/pam.d/common-auth file with the following command:
# grep pam_pkcs11.so /etc/pam.d/common-auth
auth sufficient pam_pkcs11.so
For general information about enabling smart card authentication, consult
the documentation at:
Rationale:Smart card login provides two-factor authentication stronger than
that provided by a username and password combination. Smart cards leverage PKI
(public key infrastructure) in order to provide and verify credentials.
Using an authentication device, such as a CAC or token that is separate
from the information system, ensures that even if the information system is
compromised, that compromise will not affect credentials stored on the
authentication device.
Multifactor solutions that require devices separate from information
systems gaining access include, for example, hardware tokens providing
time-based or challenge-response authenticators and smart cards such as the
U.S. Government Personal Identity Verification card and the DoD Common
Access Card. Identifiers:
CCE-85556-9 References:
CCI-000765, CCI-000766, CCI-000767, CCI-000768, CCI-000187, CCI-001948, CCI-001953, CCI-001954, SRG-OS-000068-GPOS-00036, SRG-OS-000105-GPOS-00052, SRG-OS-000106-GPOS-00053, SRG-OS-000107-GPOS-00054, SRG-OS-000108-GPOS-00055, SRG-OS-000375-GPOS-00160, SRG-OS-000375-GPOS-00161, SRG-OS-000375-GPOS-00162, SLES-15-020030, SV-234869r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather list of packages
package_facts:
manager: auto
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85556-9
- DISA-STIG-SLES-15-020030
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- smartcard_pam_enabled
- name: Check to see if 'pam_pkcs11' module is configured in '/etc/pam.d/common-auth'
shell: grep -E '^\s*auth\s+\S+\s+pam_pkcs11\.so' /etc/pam.d/common-auth || true
register: check_pam_pkcs11_module_result
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"pam_pkcs11" in ansible_facts.packages'
tags:
- CCE-85556-9
- DISA-STIG-SLES-15-020030
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- smartcard_pam_enabled
- name: Configure 'pam_pkcs11' module in '/etc/pam.d/common-auth'
lineinfile:
path: /etc/pam.d/common-auth
line: auth sufficient pam_pkcs11.so
insertafter: ^\s*#
state: present
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"pam_pkcs11" in ansible_facts.packages'
- '"pam_pkcs11.so" not in check_pam_pkcs11_module_result.stdout'
tags:
- CCE-85556-9
- DISA-STIG-SLES-15-020030
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- smartcard_pam_enabled
- name: Ensure 'pam_pkcs11' module has 'sufficient' control flag
lineinfile:
path: /etc/pam.d/common-auth
regexp: ^(\s*auth\s+)\S+(\s+pam_pkcs11\.so.*)
line: \g<1>sufficient\g<2>
backrefs: true
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"pam_pkcs11" in ansible_facts.packages'
tags:
- CCE-85556-9
- DISA-STIG-SLES-15-020030
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- smartcard_pam_enabled
|
Disable Ctrl-Alt-Del Burst Action
[ref]ruleBy default, SystemD will reboot the system if the Ctrl-Alt-Del
key sequence is pressed Ctrl-Alt-Delete more than 7 times in 2 seconds.
To configure the system to ignore the CtrlAltDelBurstAction
setting, add or modify the following to /etc/systemd/system.conf :
CtrlAltDelBurstAction=none Warning:
Disabling the Ctrl-Alt-Del key sequence
in /etc/init/control-alt-delete.conf DOES NOT disable the Ctrl-Alt-Del
key sequence if running in runlevel 6 (e.g. in GNOME, KDE, etc.)! The
Ctrl-Alt-Del key sequence will only be disabled if running in
the non-graphical runlevel 3 . Rationale:A locally logged-in user who presses Ctrl-Alt-Del, when at the console,
can reboot the system. If accidentally pressed, as could happen in
the case of mixed OS environment, this can create the risk of short-term
loss of availability of systems due to unintentional reboot. Identifiers:
CCE-85665-8 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.4.5, CCI-000366, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-3 R5.1.1, CIP-003-3 R5.3, CIP-004-3 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(b), CM-6.1(iv), PR.AC-4, PR.DS-5, SRG-OS-000324-GPOS-00125, SRG-OS-000480-GPOS-00227, SLES-15-040062, SV-234990r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q systemd; then
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/systemd/system.conf"; then
sed_command+=('--follow-symlinks')
fi
# If the cce arg is empty, CCE is not assigned.
if [ -z "CCE-85665-8" ]; then
cce="CCE"
else
cce="CCE-85665-8"
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^CtrlAltDelBurstAction=")
# shellcheck disable=SC2059
printf -v formatted_output "%s=%s" "$stripped_key" "none"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^CtrlAltDelBurstAction=\\>" "/etc/systemd/system.conf"; then
"${sed_command[@]}" "s/^CtrlAltDelBurstAction=\\>.*/$formatted_output/gi" "/etc/systemd/system.conf"
else
# \n is precaution for case where file ends without trailing newline
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/systemd/system.conf" >> "/etc/systemd/system.conf"
printf '%s\n' "$formatted_output" >> "/etc/systemd/system.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85665-8
- DISA-STIG-SLES-15-040062
- NIST-800-171-3.4.5
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- disable_ctrlaltdel_burstaction
- disable_strategy
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- name: Disable Ctrl-Alt-Del Burst Action
lineinfile:
dest: /etc/systemd/system.conf
state: present
regexp: ^CtrlAltDelBurstAction
line: CtrlAltDelBurstAction=none
create: true
when: '"systemd" in ansible_facts.packages'
tags:
- CCE-85665-8
- DISA-STIG-SLES-15-040062
- NIST-800-171-3.4.5
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- disable_ctrlaltdel_burstaction
- disable_strategy
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
|
Disable Ctrl-Alt-Del Reboot Activation
[ref]ruleBy default, SystemD will reboot the system if the Ctrl-Alt-Del
key sequence is pressed.
To configure the system to ignore the Ctrl-Alt-Del key sequence from the
command line instead of rebooting the system, do either of the following:
ln -sf /dev/null /etc/systemd/system/ctrl-alt-del.target
or
systemctl mask ctrl-alt-del.target
Do not simply delete the /usr/lib/systemd/system/ctrl-alt-del.service file,
as this file may be restored during future system updates.Rationale:A locally logged-in user who presses Ctrl-Alt-Del, when at the console,
can reboot the system. If accidentally pressed, as could happen in
the case of mixed OS environment, this can create the risk of short-term
loss of availability of systems due to unintentional reboot. Identifiers:
CCE-85625-2 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.4.5, CCI-000366, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-3 R5.1.1, CIP-003-3 R5.3, CIP-004-3 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000324-GPOS-00125, SRG-OS-000480-GPOS-00227, SLES-15-040060, SV-234988r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
systemctl disable --now ctrl-alt-del.target
systemctl mask --now ctrl-alt-del.target
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
- name: Disable Ctrl-Alt-Del Reboot Activation
systemd:
name: ctrl-alt-del.target
force: true
masked: true
state: stopped
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85625-2
- DISA-STIG-SLES-15-040060
- NIST-800-171-3.4.5
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- disable_ctrlaltdel_reboot
- disable_strategy
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
|
Protect Accounts by Restricting Password-Based Login
[ref]groupConventionally, Unix shell accounts are accessed by
providing a username and password to a login program, which tests
these values for correctness using the /etc/passwd and
/etc/shadow files. Password-based login is vulnerable to
guessing of weak passwords, and to sniffing and man-in-the-middle
attacks against passwords entered over a network or at an insecure
console. Therefore, mechanisms for accessing accounts by entering
usernames and passwords should be restricted to those which are
operationally necessary. |
contains 12 rules |
Set Account Expiration Parameters
[ref]groupAccounts can be configured to be automatically disabled
after a certain time period,
meaning that they will require administrator interaction to become usable again.
Expiration of accounts after inactivity can be set for all accounts by default
and also on a per-account basis, such as for accounts that are known to be temporary.
To configure automatic expiration of an account following
the expiration of its password (that is, after the password has expired and not been changed),
run the following command, substituting NUM_DAYS and USER appropriately:
$ sudo chage -I NUM_DAYS USER
Accounts, such as temporary accounts, can also be configured to expire on an explicitly-set date with the
-E option.
The file /etc/default/useradd controls
default settings for all newly-created accounts created with the system's
normal command line utilities.Warning:
This will only apply to newly created accounts |
contains 3 rules |
Set Account Expiration Following Inactivity
[ref]ruleTo specify the number of days after a password expires (which
signifies inactivity) until an account is permanently disabled, add or correct
the following line in /etc/default/useradd :
INACTIVE=35
If a password is currently on the verge of expiration, then
35
day(s) remain(s) until the account is automatically
disabled. However, if the password will not expire for another 60 days, then 60
days plus 35 day(s) could
elapse until the account would be automatically disabled. See the
useradd man page for more information.Rationale:Disabling inactive accounts ensures that accounts which may not
have been responsibly removed are not available to attackers
who may have compromised their credentials. Identifiers:
CCE-85558-5 References:
5.4.1.5, 1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8, 5.6.2.1.1, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.5.6, CCI-000017, CCI-000795, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2, A.12.4.1, A.12.4.3, A.18.1.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-3 R2.2.2, CIP-004-3 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, IA-4(e), AC-2(3), CM-6(a), DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, Req-8.1.4, SRG-OS-000118-GPOS-00060, SLES-15-020050, SV-234871r622137_rule, SRG-OS-000003-VMM-000030, SRG-OS-000118-VMM-000590 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85558-5
- CJIS-5.6.2.1.1
- DISA-STIG-SLES-15-020050
- NIST-800-171-3.5.6
- NIST-800-53-AC-2(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-4(e)
- PCI-DSS-Req-8.1.4
- account_disable_post_pw_expiration
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_account_disable_post_pw_expiration # promote to variable
set_fact:
var_account_disable_post_pw_expiration: !!str 35
tags:
- always
- name: Set Account Expiration Following Inactivity
lineinfile:
create: true
dest: /etc/default/useradd
regexp: ^INACTIVE
line: INACTIVE={{ var_account_disable_post_pw_expiration }}
when: '"shadow" in ansible_facts.packages'
tags:
- CCE-85558-5
- CJIS-5.6.2.1.1
- DISA-STIG-SLES-15-020050
- NIST-800-171-3.5.6
- NIST-800-53-AC-2(3)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-4(e)
- PCI-DSS-Req-8.1.4
- account_disable_post_pw_expiration
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Never Automatically Remove or Disable Emergency Administrator Accounts
[ref]ruleEmergency accounts are privileged accounts that are established in response
to crisis situations where the need for rapid account activation is
required. Therefore, emergency account activation may bypass normal account
authorization processes. If these accounts are automatically disabled,
system maintenance during emergencies may not be possible, thus adversely
affecting system availability.
Check to see if an emergency administrator account password or account expires with the following command:
# sudo chage -l [Emergency_Administrator]
Password expires:never
If Password expires or Account expires is set to anything other than never , this is a finding.Rationale:Emergency accounts are different from infrequently used accounts (i.e.,
local logon accounts used by the organization's system administrators when
network or normal logon/access is not available). Infrequently used
accounts are not subject to automatic termination dates. Emergency accounts
are accounts created in response to crisis situations, usually for use by
maintenance personnel. The automatic expiration or disabling time period
may be extended as needed until the crisis is resolved; however, it must
not be extended indefinitely. A permanent account should be established for
privileged users who need long-term maintenance accounts.
To address access requirements the SUSE operating system can be integrated
with enterprise-level authentication/access mechanisms that meet or exceed
access control policy requirements. |
Assign Expiration Date to Temporary Accounts
[ref]ruleTemporary accounts are established as part of normal account activation
procedures when there is a need for short-term accounts. In the event
temporary or emergency accounts are required, configure the system to
terminate them after a documented time period. For every temporary and
emergency account, run the following command to set an expiration date on
it, substituting USER and YYYY-MM-DD
appropriately:
$ sudo chage -E YYYY-MM-DD USER
YYYY-MM-DD indicates the documented expiration date for the
account. For U.S. Government systems, the operating system must be
configured to automatically terminate these types of accounts after a
period of 72 hours.Rationale:If temporary user accounts remain active when no longer needed or for
an excessive period, these accounts may be used to gain unauthorized access.
To mitigate this risk, automated termination of all temporary accounts
must be set upon account creation.
Identifiers:
CCE-85553-6 References:
1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS06.03, CCI-000016, CCI-001682, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2, A.12.4.1, A.12.4.3, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, AC-2(2), AC-2(3), CM-6(a), DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, SRG-OS-000123-GPOS-00064, SRG-OS-000002-GPOS-00002, SLES-15-020000, SV-234866r622137_rule, SRG-OS-000002-VMM-000020, SRG-OS-000123-VMM-000620 |
Set Password Expiration Parameters
[ref]groupThe file /etc/login.defs controls several
password-related settings. Programs such as passwd ,
su , and
login consult /etc/login.defs to determine
behavior with regard to password aging, expiration warnings,
and length. See the man page login.defs(5) for more information.
Users should be forced to change their passwords, in order to
decrease the utility of compromised passwords. However, the need to
change passwords often should be balanced against the risk that
users will reuse or write down passwords if forced to change them
too often. Forcing password changes every 90-360 days, depending on
the environment, is recommended. Set the appropriate value as
PASS_MAX_DAYS and apply it to existing accounts with the
-M flag.
The PASS_MIN_DAYS (-m ) setting prevents password
changes for 7 days after the first change, to discourage password
cycling. If you use this setting, train users to contact an administrator
for an emergency password change in case a new password becomes
compromised. The PASS_WARN_AGE (-W ) setting gives
users 7 days of warnings at login time that their passwords are about to expire.
For example, for each existing human user USER, expiration parameters
could be adjusted to a 180 day maximum password age, 7 day minimum password
age, and 7 day warning period with the following command:
$ sudo chage -M 180 -m 7 -W 7 USER |
contains 3 rules |
Set Password Maximum Age
[ref]ruleTo specify password maximum age for new accounts,
edit the file /etc/login.defs
and add or correct the following line:
PASS_MAX_DAYS 60
A value of 180 days is sufficient for many environments.
The DoD requirement is 60.
The profile requirement is 60 .Rationale:Any password, no matter how complex, can eventually be cracked. Therefore, passwords
need to be changed periodically. If the operating system does not limit the lifetime
of passwords and force users to change their passwords, there is the risk that the
operating system passwords could be compromised.
Setting the password maximum age ensures users are required to
periodically change their passwords. Requiring shorter password lifetimes
increases the risk of users writing down the password in a convenient
location subject to physical compromise. Identifiers:
CCE-85570-0 References:
BP28(R18), 5.4.1.2, 1, 12, 15, 16, 5, 5.6.2.1, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.5.6, CCI-000199, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 0418, 1055, 1402, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(f), IA-5(1)(d), CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.2.4, SRG-OS-000076-GPOS-00044, SLES-15-020220, SV-234891r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85570-0
- CJIS-5.6.2.1
- DISA-STIG-SLES-15-020220
- NIST-800-171-3.5.6
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(d)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.4
- accounts_maximum_age_login_defs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_accounts_maximum_age_login_defs # promote to variable
set_fact:
var_accounts_maximum_age_login_defs: !!str 60
tags:
- always
- name: Set Password Maximum Age
lineinfile:
create: true
dest: /etc/login.defs
regexp: ^#?PASS_MAX_DAYS
line: PASS_MAX_DAYS {{ var_accounts_maximum_age_login_defs }}
when: '"shadow" in ansible_facts.packages'
tags:
- CCE-85570-0
- CJIS-5.6.2.1
- DISA-STIG-SLES-15-020220
- NIST-800-171-3.5.6
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(d)
- NIST-800-53-IA-5(f)
- PCI-DSS-Req-8.2.4
- accounts_maximum_age_login_defs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Set Existing Passwords Maximum Age
[ref]ruleConfigure non-compliant accounts to enforce a 60-day maximum password lifetime
restriction by running the following command:
$ sudo chage -M 60 USER Rationale:Any password, no matter how complex, can eventually be cracked. Therefore,
passwords need to be changed periodically. If the operating system does
not limit the lifetime of passwords and force users to change their
passwords, there is the risk that the operating system passwords could be
compromised. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
#!/bin/bash
SECURE_MAX_PASS_AGE=60
usrs_max_pass_age=( $(awk -F: '$5 > SECURE_MAX_PASS_AGE || $5 == "" {print $1}' /etc/shadow) )
for i in ${usrs_max_pass_age[@]};
do
passwd -x $SECURE_MAX_PASS_AGE $i
done
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Collect users with not correct maximum time period between password changes
command: |
awk -F: '$5 > 60 || $5 == "" {print $1}' /etc/shadow
register: user_names
tags:
- CCE-85571-8
- DISA-STIG-SLES-15-020230
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(d)
- NIST-800-53-IA-5(f)
- accounts_password_set_max_life_existing
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Change the maximum time period between password changes
command: |
chage -M 60 {{ item }}
with_items: '{{ user_names.stdout_lines }}'
when: user_names.stdout_lines | length > 0
tags:
- CCE-85571-8
- DISA-STIG-SLES-15-020230
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(d)
- NIST-800-53-IA-5(f)
- accounts_password_set_max_life_existing
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Set Existing Passwords Minimum Age
[ref]ruleConfigure non-compliant accounts to enforce a 24 hours/1 day minimum password
lifetime by running the following command:
$ sudo chage -m 1 USER Rationale:Enforcing a minimum password lifetime helps to prevent repeated password
changes to defeat the password reuse or history enforcement requirement. If
users are allowed to immediately and continually change their password, the
password could be repeatedly changed in a short period of time to defeat the
organization's policy regarding password reuse. |
Verify Proper Storage and Existence of Password
Hashes
[ref]groupBy default, password hashes for local accounts are stored
in the second field (colon-separated) in
/etc/shadow . This file should be readable only by
processes running with root credentials, preventing users from
casually accessing others' password hashes and attempting
to crack them.
However, it remains possible to misconfigure the system
and store password hashes
in world-readable files such as /etc/passwd , or
to even store passwords themselves in plaintext on the system.
Using system-provided tools for password change/creation
should allow administrators to avoid such misconfiguration. |
contains 2 rules |
Verify All Account Password Hashes are Shadowed with SHA512
[ref]ruleVerify the operating system requires the shadow password suite
configuration be set to encrypt interactive user passwords using a strong
cryptographic hash.
Check that the interactive user account passwords are using a strong
password hash with the following command:
# sudo cut -d: -f2 /etc/shadow
$6$kcOnRq/5$NUEYPuyL.wghQwWssXRcLRFiiru7f5JPV6GaJhNC2aK5F3PZpE/BCCtwrxRc/AInKMNX3CdMw11m9STiql12f/
Password hashes ! or * indicate inactive accounts not
available for logon and are not evaluated.
If any interactive user password hash does not begin with $6 ,
this is a finding.Rationale:The system must use a strong hashing algorithm to store the password. The
system must use a sufficient number of hashing rounds to ensure the required
level of entropy. |
Prevent Login to Accounts With Empty Password
[ref]ruleIf an account is configured for password authentication
but does not have an assigned password, it may be possible to log
into the account without authentication. Remove any instances of the
nullok in
password authentication configurations in /etc/pam.d/
to prevent logins with empty passwords.
Note that this rule is not applicable for systems running within a
container. Having user with empty password within a container is not
considered a risk, because it should not be possible to directly login into
a container anyway. Rationale:If an account has an empty password, anyone could log in and
run commands with the privileges of that account. Accounts with
empty passwords should never be used in operational environments. Identifiers:
CCE-85576-7 References:
1, 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2, APO01.06, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.02, DSS06.03, DSS06.10, 3.1.1, 3.1.5, CCI-000366, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.18.1.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, IA-5(1)(a), IA-5(c), CM-6(a), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.DS-5, FIA_UAU.1, Req-8.2.3, SRG-OS-000480-GPOS-00227, SLES-15-020300, SV-234898r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
sed --follow-symlinks -i 's/\<nullok\>//g' /etc/pam.d/system-auth
sed --follow-symlinks -i 's/\<nullok\>//g' /etc/pam.d/password-auth
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Strategy: | configure |
---|
- name: Find files in /etc/pam.d/ with password auth
find:
paths: /etc/pam.d
contains: .*pam_unix\.so.*nullok.*
recurse: true
register: find_pam_conf_files_result
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85576-7
- CJIS-5.5.2
- DISA-STIG-SLES-15-020300
- NIST-800-171-3.1.1
- NIST-800-171-3.1.5
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.3
- configure_strategy
- high_severity
- low_complexity
- medium_disruption
- no_empty_passwords
- no_reboot_needed
- name: Prevent Log In to Accounts with Empty Password
replace:
dest: '{{ item.path }}'
regexp: nullok
with_items: '{{ find_pam_conf_files_result.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85576-7
- CJIS-5.5.2
- DISA-STIG-SLES-15-020300
- NIST-800-171-3.1.1
- NIST-800-171-3.1.5
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)(a)
- NIST-800-53-IA-5(c)
- PCI-DSS-Req-8.2.3
- configure_strategy
- high_severity
- low_complexity
- medium_disruption
- no_empty_passwords
- no_reboot_needed
|
Restrict Root Logins
[ref]groupDirect root logins should be allowed only for emergency use.
In normal situations, the administrator should access the system
via a unique unprivileged account, and then use su or sudo to execute
privileged commands. Discouraging administrators from accessing the
root account directly ensures an audit trail in organizations with
multiple administrators. Locking down the channels through which
root can connect directly also reduces opportunities for
password-guessing against the root account. The login program
uses the file /etc/securetty to determine which interfaces
should allow root logins.
The virtual devices /dev/console
and /dev/tty* represent the system consoles (accessible via
the Ctrl-Alt-F1 through Ctrl-Alt-F6 keyboard sequences on a default
installation). The default securetty file also contains /dev/vc/* .
These are likely to be deprecated in most environments, but may be retained
for compatibility. Root should also be prohibited from connecting
via network protocols. Other sections of this document
include guidance describing how to prevent root from logging in via SSH. |
contains 2 rules |
Verify Only Root Has UID 0
[ref]ruleIf any account other than root has a UID of 0, this misconfiguration should
be investigated and the accounts other than root should be removed or have
their UID changed.
If the account is associated with system commands or applications the UID
should be changed to one greater than "0" but less than "1000."
Otherwise assign a UID greater than "1000" that has not already been
assigned. Rationale:An account has root authority if it has a UID of 0. Multiple accounts
with a UID of 0 afford more opportunity for potential intruders to
guess a password for a privileged account. Proper configuration of
sudo is recommended to afford multiple system administrators
access to root privileges in an accountable manner. Identifiers:
CCE-85664-1 References:
6.2.3, 1, 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.02, DSS06.03, DSS06.10, 3.1.1, 3.1.5, CCI-000366, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.18.1.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-003-3 R5.1.1, CIP-003-3 R5.3, CIP-004-3 R2.2.3, CIP-004-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, CM-6(b), CM-6.1(iv), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.DS-5, SRG-OS-000480-GPOS-00227, SLES-15-020100, SV-234876r622137_rule Remediation Shell script: (show)
awk -F: '$3 == 0 && $1 != "root" { print $1 }' /etc/passwd | xargs --max-lines=1 passwd -l
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: get all /etc/passwd file entries
getent:
database: passwd
split: ':'
tags:
- CCE-85664-1
- DISA-STIG-SLES-15-020100
- NIST-800-171-3.1.1
- NIST-800-171-3.1.5
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- accounts_no_uid_except_zero
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- restrict_strategy
- name: lock the password of the user accounts other than root with uid 0
command: passwd -l {{ item.key }}
loop: '{{ getent_passwd | dict2items | rejectattr(''key'', ''search'', ''root'')
| list }}'
when: item.value.1 == '0'
tags:
- CCE-85664-1
- DISA-STIG-SLES-15-020100
- NIST-800-171-3.1.1
- NIST-800-171-3.1.5
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- accounts_no_uid_except_zero
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- restrict_strategy
|
Ensure that System Accounts Do Not Run a Shell Upon Login
[ref]ruleSome accounts are not associated with a human user of the system, and exist to
perform some administrative function. Should an attacker be able to log into
these accounts, they should not be granted access to a shell.
The login shell for each local account is stored in the last field of each line
in /etc/passwd . System accounts are those user accounts with a user ID
less than UID_MIN, where value of UID_MIN directive is set in
/etc/login.defs configuration file. In the default configuration UID_MIN is set
to 1000, thus system accounts are those user accounts with a user ID less than
1000. The user ID is stored in the third field. If any system account
SYSACCT (other than root) has a login shell, disable it with the
command: $ sudo usermod -s /sbin/nologin SYSACCT Warning:
Do not perform the steps in this section on the root account. Doing so might
cause the system to become inaccessible. Rationale:Ensuring shells are not given to system accounts upon login makes it more
difficult for attackers to make use of system accounts. Identifiers:
CCE-85672-4 References:
5.4.2, 1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS06.03, CCI-000366, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2, 1491, A.12.4.1, A.12.4.3, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, AC-6, CM-6(a), CM-6(b), CM-6.1(iv), DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, SRG-OS-000480-GPOS-00227, SLES-15-020091, SV-234875r622137_rule |
Ensure All Accounts on the System Have Unique User IDs
[ref]ruleChange user IDs (UIDs), or delete accounts, so each has a unique name. Rationale:To assure accountability and prevent unauthenticated access, interactive users must be identified and authenticated to prevent potential misuse and compromise of the system. |
Only Authorized Local User Accounts Exist on Operating System
[ref]ruleEnterprise Application tends to use the server or virtual machine exclusively.
Besides the default operating system user, there should be only authorized local
users required by the installed softoware groups and applications that exist on
the operating system. The authorized user list can be customized in the refine
value variable var_accounts_authorized_local_users_regex .
OVAL regular expression is used for the user list.
Configure the system so all accounts on the system are assigned to an active system,
application, or user account. Remove accounts that do not support approved system
activities or that allow for a normal user to perform administrative-level actions.
To remove unauthorized system accounts, use the following command:
$ sudo userdel unauthorized_user Rationale:Accounts providing no operational purpose provide additional opportunities for
system compromise. Unnecessary accounts include user accounts for individuals not
requiring access to the system and application accounts for applications not installed
on the system. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_accounts_authorized_local_users_regex # promote to variable
set_fact:
var_accounts_authorized_local_users_regex: !!str (N/A)
tags:
- always
- name: Read /etc/shadow
getent:
database: shadow
tags:
- CCE-85561-9
- DISA-STIG-SLES-15-020090
- accounts_authorized_local_users
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Remove unauthorized accounts
user:
name: '{{ item.key }}'
force: true
state: absent
when: item.key is not regex(var_accounts_authorized_local_users_regex)
with_dict: '{{ getent_shadow }}'
tags:
- CCE-85561-9
- DISA-STIG-SLES-15-020090
- accounts_authorized_local_users
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Secure Session Configuration Files for Login Accounts
[ref]groupWhen a user logs into a Unix account, the system
configures the user's session by reading a number of files. Many of
these files are located in the user's home directory, and may have
weak permissions as a result of user error or misconfiguration. If
an attacker can modify or even read certain types of account
configuration information, they can often gain full access to the
affected user's account. Therefore, it is important to test and
correct configuration file permissions for interactive accounts,
particularly those of privileged users such as root or system
administrators. |
contains 11 rules |
Ensure that Users Have Sensible Umask Values
[ref]groupThe umask setting controls the default permissions
for the creation of new files.
With a default umask setting of 077, files and directories
created by users will not be readable by any other user on the
system. Users who wish to make specific files group- or
world-readable can accomplish this by using the chmod command.
Additionally, users can make all their files readable to their
group by default by setting a umask of 027 in their shell
configuration files. If default per-user groups exist (that is, if
every user has a default group whose name is the same as that
user's username and whose only member is the user), then it may
even be safe for users to select a umask of 007, making it very
easy to intentionally share files with groups of which the user is
a member.
|
contains 1 rule |
Ensure the Default Umask is Set Correctly in login.defs
[ref]ruleTo ensure the default umask controlled by /etc/login.defs is set properly,
add or correct the UMASK setting in /etc/login.defs to read as follows:
UMASK 027 Rationale:The umask value influences the permissions assigned to files when they are created.
A misconfigured umask value could result in files with excessive permissions that can be read and
written to by unauthorized users. Identifiers:
CCE-85659-1 References:
BP28(R35), 5.4.5, 11, 18, 3, 9, APO13.01, BAI03.01, BAI03.02, BAI03.03, BAI10.01, BAI10.02, BAI10.03, BAI10.05, CCI-000366, 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.1.1, A.14.2.1, A.14.2.2, A.14.2.3, A.14.2.4, A.14.2.5, A.6.1.5, CIP-003-3 R5.1.1, CIP-003-3 R5.3, CIP-004-3 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, AC-6(1), CM-6(a), PR.IP-1, PR.IP-2, SRG-OS-000480-GPOS-00228, SLES-15-040420, SV-235030r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q shadow; then
var_accounts_user_umask="027"
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/login.defs"; then
sed_command+=('--follow-symlinks')
fi
# If the cce arg is empty, CCE is not assigned.
if [ -z "CCE-85659-1" ]; then
cce="CCE"
else
cce="CCE-85659-1"
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^UMASK")
# shellcheck disable=SC2059
printf -v formatted_output "%s %s" "$stripped_key" "$var_accounts_user_umask"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^UMASK\\>" "/etc/login.defs"; then
"${sed_command[@]}" "s/^UMASK\\>.*/$formatted_output/gi" "/etc/login.defs"
else
# \n is precaution for case where file ends without trailing newline
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/login.defs" >> "/etc/login.defs"
printf '%s\n' "$formatted_output" >> "/etc/login.defs"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85659-1
- DISA-STIG-SLES-15-040420
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- accounts_umask_etc_login_defs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_accounts_user_umask # promote to variable
set_fact:
var_accounts_user_umask: !!str 027
tags:
- always
- name: Ensure the Default UMASK is Set Correctly
lineinfile:
create: true
dest: /etc/login.defs
regexp: ^UMASK
line: UMASK {{ var_accounts_user_umask }}
when: '"shadow" in ansible_facts.packages'
tags:
- CCE-85659-1
- DISA-STIG-SLES-15-040420
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- accounts_umask_etc_login_defs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure Home Directories are Created for New Users
[ref]ruleAll local interactive user accounts, upon creation, should be assigned a home directory.
Configure the operating system to assign home directories to all new local interactive users by setting the CREATE_HOME
parameter in /etc/login.defs to yes as follows:
CREATE_HOME yes Rationale:If local interactive users are not assigned a valid home directory, there is no place
for the storage and control of files they should own. Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q shadow; then
if [ -e "/etc/login.defs" ] ; then
LC_ALL=C sed -i "/^\s*CREATE_HOME\s\+/Id" "/etc/login.defs"
else
touch "/etc/login.defs"
fi
cp "/etc/login.defs" "/etc/login.defs.bak"
# Insert before the line matching the regex '^\s*CREATE_HOME'.
line_number="$(LC_ALL=C grep -n "^\s*CREATE_HOME" "/etc/login.defs.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^\s*CREATE_HOME', insert at
# the end of the file.
printf '%s\n' "CREATE_HOME yes" >> "/etc/login.defs"
else
head -n "$(( line_number - 1 ))" "/etc/login.defs.bak" > "/etc/login.defs"
printf '%s\n' "CREATE_HOME yes" >> "/etc/login.defs"
tail -n "+$(( line_number ))" "/etc/login.defs.bak" >> "/etc/login.defs"
fi
# Clean up after ourselves.
rm "/etc/login.defs.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85562-7
- DISA-STIG-SLES-15-020110
- accounts_have_homedir_login_defs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Ensure new users receive home directories
block:
- name: Check for duplicate values
lineinfile:
path: /etc/login.defs
create: false
regexp: ^\s*CREATE_HOME\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/login.defs
lineinfile:
path: /etc/login.defs
create: false
regexp: ^\s*CREATE_HOME\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/login.defs
lineinfile:
path: /etc/login.defs
create: true
regexp: ^\s*CREATE_HOME\s+
line: CREATE_HOME yes
state: present
when: '"shadow" in ansible_facts.packages'
tags:
- CCE-85562-7
- DISA-STIG-SLES-15-020110
- accounts_have_homedir_login_defs
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Limit the Number of Concurrent Login Sessions Allowed Per User
[ref]ruleLimiting the number of allowed users and sessions per user can limit risks related to Denial of
Service attacks. This addresses concurrent sessions for a single account and does not address
concurrent sessions by a single user via multiple accounts. To set the number of concurrent
sessions per user add the following line in /etc/security/limits.conf or
a file under /etc/security/limits.d/ :
* hard maxlogins 10 Rationale:Limiting simultaneous user logins can insulate the system from denial of service
problems caused by excessive logins. Automated login processes operating improperly or
maliciously may result in an exceptional number of simultaneous login sessions. Identifiers:
CCE-85555-1 References:
14, 15, 18, 9, 5.5.2.2, DSS01.05, DSS05.02, CCI-000054, 4.3.3.4, SR 3.1, SR 3.8, A.13.1.1, A.13.1.3, A.13.2.1, A.14.1.2, A.14.1.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, AC-10, CM-6(a), PR.AC-5, SRG-OS-000027-GPOS-00008, SLES-15-020020, SV-234868r622137_rule, SRG-OS-000027-VMM-000080 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85555-1
- CJIS-5.5.2.2
- DISA-STIG-SLES-15-020020
- NIST-800-53-AC-10
- NIST-800-53-CM-6(a)
- accounts_max_concurrent_login_sessions
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_accounts_max_concurrent_login_sessions # promote to variable
set_fact:
var_accounts_max_concurrent_login_sessions: !!str 10
tags:
- always
- name: Find /etc/security/limits.d files containing maxlogins configuration
find:
paths: /etc/security/limits.d
contains: ^[\s]*\*[\s]+(?:(?:hard)|(?:-))[\s]+maxlogins
patterns: '*.conf'
register: maxlogins
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85555-1
- CJIS-5.5.2.2
- DISA-STIG-SLES-15-020020
- NIST-800-53-AC-10
- NIST-800-53-CM-6(a)
- accounts_max_concurrent_login_sessions
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- restrict_strategy
- name: Limit the Number of Concurrent Login Sessions Allowed Per User in files from
limits.d
replace:
dest: '{{ item.path }}'
regexp: ^#?\*.*maxlogins.*
replace: '* hard maxlogins {{ var_accounts_max_concurrent_login_sessions
}}'
with_items:
- '{{ maxlogins.files }}'
when: '"pam" in ansible_facts.packages'
tags:
- CCE-85555-1
- CJIS-5.5.2.2
- DISA-STIG-SLES-15-020020
- NIST-800-53-AC-10
- NIST-800-53-CM-6(a)
- accounts_max_concurrent_login_sessions
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- restrict_strategy
- name: Limit the Number of Concurrent Login Sessions Allowed Per User
lineinfile:
state: present
dest: /etc/security/limits.conf
insertbefore: ^# End of file
regexp: ^#?\*.*maxlogins
line: '* hard maxlogins {{ var_accounts_max_concurrent_login_sessions
}}'
create: true
when:
- '"pam" in ansible_facts.packages'
- maxlogins.matched == 0
tags:
- CCE-85555-1
- CJIS-5.5.2.2
- DISA-STIG-SLES-15-020020
- NIST-800-53-AC-10
- NIST-800-53-CM-6(a)
- accounts_max_concurrent_login_sessions
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- restrict_strategy
|
Set Interactive Session Timeout
[ref]ruleSetting the TMOUT option in /etc/profile ensures that
all user sessions will terminate based on inactivity. The TMOUT
setting in /etc/profile.d/autologout.sh should read as follows:
TMOUT=900
readonly TMOUT
export TMOUTRationale:Terminating an idle session within a short time period reduces
the window of opportunity for unauthorized personnel to take control of a
management session enabled on the console or console port that has been
left unattended. Identifiers:
CCE-83269-1 References:
BP28(R29), 5.4.4, 1, 12, 15, 16, DSS05.04, DSS05.10, DSS06.10, 3.1.11, CCI-000057, CCI-001133, CCI-002361, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, CIP-004-3 R2.2.3, CIP-007-3 R5.1, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, AC-12, SC-10, AC-2(5), CM-6(a), PR.AC-7, FMT_MOF_EXT.1, SRG-OS-000163-GPOS-00072, SRG-OS-000029-GPOS-00010, SLES-15-010130, SV-234813r622137_rule, SRG-OS-000163-VMM-000700, SRG-OS-000279-VMM-001010 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
var_accounts_tmout="900"
# if 0, no occurence of tmout found, if 1, occurence found
tmout_found=0
for f in /etc/profile /etc/profile.d/*.sh; do
if grep --silent '^\s*TMOUT' $f; then
sed -i -E "s/^(\s*)TMOUT\s*=\s*(\w|\$)*(.*)$/\1TMOUT=$var_accounts_tmout\3/g" $f
tmout_found=1
fi
done
if [ $tmout_found -eq 0 ]; then
echo -e "\n# Set TMOUT to $var_accounts_tmout per security requirements" >> /etc/profile.d/tmout.sh
echo "TMOUT=$var_accounts_tmout" >> /etc/profile.d/tmout.sh
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_accounts_tmout # promote to variable
set_fact:
var_accounts_tmout: !!str 900
tags:
- always
- name: Set Interactive Session Timeout
block:
- name: Check for duplicate values
lineinfile:
path: /etc/profile.d/autologout.sh
create: false
regexp: ^\s*TMOUT=
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/profile.d/autologout.sh
lineinfile:
path: /etc/profile.d/autologout.sh
create: false
regexp: ^\s*TMOUT=
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/profile.d/autologout.sh
lineinfile:
path: /etc/profile.d/autologout.sh
create: true
regexp: ^\s*TMOUT=
line: TMOUT={{ var_accounts_tmout }}
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83269-1
- DISA-STIG-SLES-15-010130
- NIST-800-171-3.1.11
- NIST-800-53-AC-12
- NIST-800-53-AC-2(5)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-10
- accounts_tmout
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set Interactive Session Timeout
block:
- name: Check for duplicate values
lineinfile:
path: /etc/profile.d/autologout.sh
create: false
regexp: ^\s*readonly\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/profile.d/autologout.sh
lineinfile:
path: /etc/profile.d/autologout.sh
create: false
regexp: ^\s*readonly\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/profile.d/autologout.sh
lineinfile:
path: /etc/profile.d/autologout.sh
create: true
regexp: ^\s*readonly\s+
line: readonly TMOUT
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83269-1
- DISA-STIG-SLES-15-010130
- NIST-800-171-3.1.11
- NIST-800-53-AC-12
- NIST-800-53-AC-2(5)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-10
- accounts_tmout
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set Interactive Session Timeout
block:
- name: Check for duplicate values
lineinfile:
path: /etc/profile.d/autologout.sh
create: false
regexp: ^\s*export\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/profile.d/autologout.sh
lineinfile:
path: /etc/profile.d/autologout.sh
create: false
regexp: ^\s*export\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/profile.d/autologout.sh
lineinfile:
path: /etc/profile.d/autologout.sh
create: true
regexp: ^\s*export\s+
line: export TMOUT
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83269-1
- DISA-STIG-SLES-15-010130
- NIST-800-171-3.1.11
- NIST-800-53-AC-12
- NIST-800-53-AC-2(5)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-10
- accounts_tmout
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set the permission for /etc/profile.d/autologout.sh
file:
path: /etc/profile.d/autologout.sh
mode: '0755'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83269-1
- DISA-STIG-SLES-15-010130
- NIST-800-171-3.1.11
- NIST-800-53-AC-12
- NIST-800-53-AC-2(5)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-10
- accounts_tmout
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
User Initialization Files Must Not Run World-Writable Programs
[ref]ruleSet the mode on files being executed by the user initialization files with the
following command:
$ sudo chmod 0755 FILE Rationale:If user start-up files execute world-writable programs, especially in
unprotected directories, they could be maliciously modified to destroy user
files or otherwise compromise the system at the user level. If the system is
compromised at the user level, it is easier to elevate privileges to eventually
compromise the system at the root and network level. |
Ensure that Users Path Contains Only Local Directories
[ref]ruleEnsure that all interactive user initialization files executable search
path statements do not contain statements that will reference a working
directory other than the users home directory. Rationale:The executable search path (typically the PATH environment variable) contains a
list of directories for the shell to search to find executables. If this path
includes the current working directory (other than the users home directory),
executables in these directories may be executed instead of system commands.
This variable is formatted as a colon-separated list of directories. If there is
an empty entry, such as a leading or trailing colon or two consecutive colons,
this is interpreted as the current working directory. If deviations from the
default system search path for the local interactive user are required, they
must be documented with the Information System Security Officer (ISSO). |
All Interactive Users Must Have A Home Directory Defined
[ref]ruleAssign home directories to all interactive users that currently do not
have a home directory assigned. Rationale:If local interactive users are not assigned a valid home directory, there is no
place for the storage and control of files they should own. |
All Interactive Users Home Directories Must Exist
[ref]ruleCreate home directories to all interactive users that currently do not
have a home directory assigned. Use the following commands to create the user
home directory assigned in /etc/passwd :
$ sudo mkdir /home/USER Rationale:If a local interactive user has a home directory defined that does not exist,
the user may be given access to the / directory as the current working directory
upon logon. This could create a Denial of Service because the user would not be
able to access their logon configuration files, and it may give them visibility
to system files they normally would not be able to access. |
All Interactive User Home Directories Must Be Group-Owned By The Primary User
[ref]ruleChange the group owner of interactive users home directory to the
group found in /etc/passwd . To change the group owner of
interactive users home directory, use the following command:
$ sudo chgrp USER_GROUP /home/USER Rationale:If the Group Identifier (GID) of a local interactive users home directory is
not the same as the primary GID of the user, this would allow unauthorized
access to the users files, and users that share the same group may not be
able to access files that they legitimately should. |
Ensure All User Initialization Files Have Mode 0740 Or Less Permissive
[ref]ruleSet the mode of the user initialization files to 0740 with the
following command:
$ sudo chmod 0740 /home/USER/.INIT_FILE Rationale:Local initialization files are used to configure the user's shell environment
upon logon. Malicious modification of these files could compromise accounts upon
logon. |
All Interactive User Home Directories Must Have mode 0750 Or Less Permissive
[ref]ruleChange the mode of interactive users home directories to 0750 . To
change the mode of interactive users home directory, use the
following command:
$ sudo chmod 0750 /home/USER Rationale:Excessive permissions on local interactive user home directories may allow
unauthorized access to user files by other users. |
System Accounting with auditd
[ref]groupThe audit service provides substantial capabilities
for recording system activities. By default, the service audits about
SELinux AVC denials and certain types of security-relevant events
such as system logins, account modifications, and authentication
events performed by programs such as sudo.
Under its default configuration, auditd has modest disk space
requirements, and should not noticeably impact system performance.
NOTE: The Linux Audit daemon auditd can be configured to use
the augenrules program to read audit rules files (*.rules )
located in /etc/audit/rules.d location and compile them to create
the resulting form of the /etc/audit/audit.rules configuration file
during the daemon startup (default configuration). Alternatively, the auditd
daemon can use the auditctl utility to read audit rules from the
/etc/audit/audit.rules configuration file during daemon startup,
and load them into the kernel. The expected behavior is configured via the
appropriate ExecStartPost directive setting in the
/usr/lib/systemd/system/auditd.service configuration file.
To instruct the auditd daemon to use the augenrules program
to read audit rules (default configuration), use the following setting:
ExecStartPost=-/sbin/augenrules --load
in the /usr/lib/systemd/system/auditd.service configuration file.
In order to instruct the auditd daemon to use the auditctl
utility to read audit rules, use the following setting:
ExecStartPost=-/sbin/auditctl -R /etc/audit/audit.rules
in the /usr/lib/systemd/system/auditd.service configuration file.
Refer to [Service] section of the /usr/lib/systemd/system/auditd.service
configuration file for further details.
Government networks often have substantial auditing
requirements and auditd can be configured to meet these
requirements.
Examining some example audit records demonstrates how the Linux audit system
satisfies common requirements.
The following example from Fedora Documentation available at
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html-single/selinux_users_and_administrators_guide/index#sect-Security-Enhanced_Linux-Fixing_Problems-Raw_Audit_Messages
shows the substantial amount of information captured in a
two typical "raw" audit messages, followed by a breakdown of the most important
fields. In this example the message is SELinux-related and reports an AVC
denial (and the associated system call) that occurred when the Apache HTTP
Server attempted to access the /var/www/html/file1 file (labeled with
the samba_share_t type):
type=AVC msg=audit(1226874073.147:96): avc: denied { getattr } for pid=2465 comm="httpd"
path="/var/www/html/file1" dev=dm-0 ino=284133 scontext=unconfined_u:system_r:httpd_t:s0
tcontext=unconfined_u:object_r:samba_share_t:s0 tclass=file
type=SYSCALL msg=audit(1226874073.147:96): arch=40000003 syscall=196 success=no exit=-13
a0=b98df198 a1=bfec85dc a2=54dff4 a3=2008171 items=0 ppid=2463 pid=2465 auid=502 uid=48
gid=48 euid=48 suid=48 fsuid=48 egid=48 sgid=48 fsgid=48 tty=(none) ses=6 comm="httpd"
exe="/usr/sbin/httpd" subj=unconfined_u:system_r:httpd_t:s0 key=(null)
msg=audit(1226874073.147:96) - The number in parentheses is the unformatted time stamp (Epoch time)
for the event, which can be converted to standard time by using the
date command.
{ getattr } - The item in braces indicates the permission that was denied.
getattr
indicates the source process was trying to read the target file's status information.
This occurs before reading files. This action is denied due to the file being
accessed having the wrong label. Commonly seen permissions include getattr ,
read , and write .
comm="httpd" - The executable that launched the process. The full path of the executable is
found in the
exe= section of the system call (SYSCALL ) message,
which in this case, is exe="/usr/sbin/httpd" .
path="/var/www/html/file1" - The path to the object (target) the process attempted to access.
scontext="unconfined_u:system_r:httpd_t:s0" - The SELinux context of the process that attempted the denied action. In
this case, it is the SELinux context of the Apache HTTP Server, which is running
in the
httpd_t domain.
tcontext="unconfined_u:object_r:samba_share_t:s0" - The SELinux context of the object (target) the process attempted to access.
In this case, it is the SELinux context of
file1 . Note: the samba_share_t
type is not accessible to processes running in the httpd_t domain.
- From the system call (
SYSCALL ) message, two items are of interest:
success=no : indicates whether the denial (AVC) was enforced or not.
success=no indicates the system call was not successful (SELinux denied
access). success=yes indicates the system call was successful - this can
be seen for permissive domains or unconfined domains, such as initrc_t
and kernel_t .
exe="/usr/sbin/httpd" : the full path to the executable that launched
the process, which in this case, is exe="/usr/sbin/httpd" .
|
contains 79 rules |
Configure auditd Rules for Comprehensive Auditing
[ref]groupThe auditd program can perform comprehensive
monitoring of system activity. This section describes recommended
configuration settings for comprehensive auditing, but a full
description of the auditing system's capabilities is beyond the
scope of this guide. The mailing list linux-audit@redhat.com exists
to facilitate community discussion of the auditing system.
The audit subsystem supports extensive collection of events, including:
- Tracing of arbitrary system calls (identified by name or number)
on entry or exit.
- Filtering by PID, UID, call success, system call argument (with
some limitations), etc.
- Monitoring of specific files for modifications to the file's
contents or metadata.
Auditing rules at startup are controlled by the file /etc/audit/audit.rules .
Add rules to it to meet the auditing requirements for your organization.
Each line in /etc/audit/audit.rules represents a series of arguments
that can be passed to auditctl and can be individually tested
during runtime. See documentation in /usr/share/doc/audit-VERSION and
in the related man pages for more details.
If copying any example audit rulesets from /usr/share/doc/audit-VERSION ,
be sure to comment out the
lines containing arch= which are not appropriate for your system's
architecture. Then review and understand the following rules,
ensuring rules are activated as needed for the appropriate
architecture.
After reviewing all the rules, reading the following sections, and
editing as needed, the new rules can be activated as follows:
$ sudo service auditd restart |
contains 69 rules |
Record Events that Modify the System's Discretionary Access Controls
[ref]groupAt a minimum, the audit system should collect file permission
changes for all users and root. Note that the "-F arch=b32" lines should be
present even on a 64 bit system. These commands identify system calls for
auditing. Even if the system is 64 bit it can still execute 32 bit system
calls. Additionally, these rules can be configured in a number of ways while
still achieving the desired effect. An example of this is that the "-S" calls
could be split up and placed on separate lines, however, this is less efficient.
Add the following to /etc/audit/audit.rules :
-a always,exit -F arch=b32 -S chmod,fchmod,fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b32 -S chown,fchown,fchownat,lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b32 -S setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If your system is 64 bit then these lines should be duplicated and the
arch=b32 replaced with arch=b64 as follows:
-a always,exit -F arch=b64 -S chmod,fchmod,fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b64 -S chown,fchown,fchownat,lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
-a always,exit -F arch=b64 -S setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod |
contains 15 rules |
Record Events that Modify the System's Discretionary Access Controls - chmod
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured to
use the augenrules program to read audit rules during daemon startup
(the default), add the following line to a file with suffix .rules in
the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-85693-0 References:
4.1.9, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-3, AU-3.1, AU-12(c), AU-12.1(iv), AU-12(a), AU-12.1(ii), MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SLES-15-030290, SV-234928r622137_rule, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="chmod"
KEY="perm_mod"
SYSCALL_GROUPING="chmod fchmod fchmodat"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85693-0
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030290
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_chmod
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit chmod tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85693-0
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030290
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_chmod
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for chmod for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- chmod
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of chmod in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- chmod
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of chmod in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85693-0
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030290
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_chmod
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for chmod for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- chmod
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of chmod in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- chmod
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of chmod in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85693-0
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030290
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_chmod
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Events that Modify the System's Discretionary Access Controls - chown
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured to
use the augenrules program to read audit rules during daemon startup
(the default), add the following line to a file with suffix .rules in
the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-85690-6 References:
4.1.9, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-3, AU-3.1, AU-12(c), AU-12.1(iv), AU-12(a), AU-12.1(ii), MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219, SLES-15-030250, SV-234924r622137_rule, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="chown"
KEY="perm_mod"
SYSCALL_GROUPING="chown fchown fchownat lchown"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85690-6
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030250
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_chown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit chown tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85690-6
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030250
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_chown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for chown for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- chown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of chown in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- chown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of chown in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85690-6
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030250
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_chown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for chown for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- chown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of chown in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- chown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of chown in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85690-6
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030250
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_chown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Events that Modify the System's Discretionary Access Controls - fchmod
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured to
use the augenrules program to read audit rules during daemon startup
(the default), add the following line to a file with suffix .rules in
the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-85694-8 References:
4.1.9, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-3, AU-3.1, AU-12(c), AU-12.1(iv), AU-12(a), AU-12.1(ii), MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SLES-15-030300, SV-234929r622137_rule, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="fchmod"
KEY="perm_mod"
SYSCALL_GROUPING="chmod fchmod fchmodat"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85694-8
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030300
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchmod
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit fchmod tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85694-8
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030300
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchmod
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fchmod for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fchmod
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of fchmod in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fchmod
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of fchmod in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85694-8
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030300
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchmod
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fchmod for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fchmod
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of fchmod in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fchmod
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of fchmod in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85694-8
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030300
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchmod
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Events that Modify the System's Discretionary Access Controls - fchmodat
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured to
use the augenrules program to read audit rules during daemon startup
(the default), add the following line to a file with suffix .rules in
the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-85695-5 References:
4.1.9, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-3, AU-3.1, AU-12(c), AU-12.1(iv), AU-12(a), AU-12.1(ii), MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SLES-15-030310, SV-234930r622137_rule, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="fchmodat"
KEY="perm_mod"
SYSCALL_GROUPING="chmod fchmod fchmodat"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85695-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030310
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchmodat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit fchmodat tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85695-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030310
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchmodat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fchmodat for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fchmodat
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of fchmodat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fchmodat
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of fchmodat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85695-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030310
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchmodat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fchmodat for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fchmodat
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of fchmodat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fchmodat
syscall_grouping:
- chmod
- fchmod
- fchmodat
- name: Check existence of fchmodat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85695-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030310
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchmodat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Events that Modify the System's Discretionary Access Controls - fchown
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-85721-9 References:
4.1.9, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-3, AU-3.1, AU-12(c), AU-12.1(iv), AU-12(a), AU-12.1(ii), MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219, SLES-15-030260, SV-234925r622137_rule, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="fchown"
KEY="perm_mod"
SYSCALL_GROUPING="chown fchown fchownat lchown"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85721-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030260
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit fchown tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85721-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030260
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fchown for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fchown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of fchown in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fchown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of fchown in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85721-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030260
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fchown for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fchown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of fchown in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fchown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of fchown in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85721-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030260
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Events that Modify the System's Discretionary Access Controls - fchownat
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-85692-2 References:
4.1.9, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-3, AU-3.1, AU-12(c), AU-12.1(iv), AU-12(a), AU-12.1(ii), MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219, SLES-15-030280, SV-234927r622137_rule, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="fchownat"
KEY="perm_mod"
SYSCALL_GROUPING="chown fchown fchownat lchown"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85692-2
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030280
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchownat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit fchownat tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85692-2
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030280
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchownat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fchownat for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fchownat
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of fchownat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fchownat
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of fchownat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85692-2
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030280
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchownat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fchownat for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fchownat
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of fchownat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fchownat
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of fchownat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85692-2
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030280
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fchownat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Events that Modify the System's Discretionary Access Controls - fremovexattr
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root.
If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-85686-4 References:
4.1.9, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-12(a), AU-12.1(ii), AU-12(c), AU-12.1(iv), AU-3, AU-3.1, MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000466-GPOS-00210, SRG-OS-000064-GPOS-00033, SLES-15-030210, SV-234920r622137_rule, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="fremovexattr"
KEY="perm_mod"
SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85686-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030210
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fremovexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit fremovexattr tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85686-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030210
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fremovexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fremovexattr for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fremovexattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fremovexattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85686-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030210
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fremovexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fremovexattr for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fremovexattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fremovexattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85686-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030210
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fremovexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Events that Modify the System's Discretionary Access Controls - fsetxattr
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-85688-0 References:
4.1.9, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-12(a), AU-12.1(ii), AU-12(c), AU-12.1(iv), AU-3, AU-3.1, MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000064-GPOS-00033, SLES-15-030230, SV-234922r622137_rule, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="fsetxattr"
KEY="perm_mod"
SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85688-0
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030230
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fsetxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit fsetxattr tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85688-0
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030230
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fsetxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fsetxattr for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fsetxattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fsetxattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85688-0
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030230
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fsetxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for fsetxattr for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- fsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fsetxattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- fsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of fsetxattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85688-0
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030230
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_fsetxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Events that Modify the System's Discretionary Access Controls - lchown
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-85691-4 References:
4.1.9, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-3, AU-3.1, AU-12(c), AU-12.1(iv), AU-12(a), AU-12.1(ii), MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219, SLES-15-030270, SV-234926r622137_rule, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="lchown"
KEY="perm_mod"
SYSCALL_GROUPING="chown fchown fchownat lchown"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85691-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030270
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_lchown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit lchown tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85691-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030270
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_lchown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for lchown for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- lchown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of lchown in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- lchown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of lchown in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85691-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030270
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_lchown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for lchown for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- lchown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of lchown in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- lchown
syscall_grouping:
- chown
- fchown
- fchownat
- lchown
- name: Check existence of lchown in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85691-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030270
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_lchown
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Events that Modify the System's Discretionary Access Controls - lremovexattr
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root.
If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-85685-6 References:
4.1.9, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-3, AU-3.1, AU-12(c), AU-12.1(iv), AU-12(a), AU-12.1(ii), MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000466-GPOS-00210, SRG-OS-000064-GPOS-00033, SLES-15-030200, SV-234919r622137_rule, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="lremovexattr"
KEY="perm_mod"
SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85685-6
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030200
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_lremovexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit lremovexattr tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85685-6
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030200
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_lremovexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for lremovexattr for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- lremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lremovexattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- lremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lremovexattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85685-6
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030200
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_lremovexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for lremovexattr for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- lremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lremovexattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- lremovexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lremovexattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85685-6
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030200
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_lremovexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Events that Modify the System's Discretionary Access Controls - lsetxattr
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-85689-8 References:
4.1.9, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-12(a), AU-12.1(ii), AU-12(c), AU-12.1(iv), AU-3, AU-3.1, MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000064-GPOS-00033, SLES-15-030240, SV-234923r622137_rule, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="lsetxattr"
KEY="perm_mod"
SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85689-8
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030240
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_lsetxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit lsetxattr tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85689-8
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030240
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_lsetxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for lsetxattr for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- lsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lsetxattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- lsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lsetxattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85689-8
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030240
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_lsetxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for lsetxattr for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- lsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lsetxattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- lsetxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of lsetxattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85689-8
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030240
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_lsetxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Events that Modify the System's Discretionary Access Controls - removexattr
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root.
If the auditd daemon is configured to use the augenrules
program to read audit rules during daemon startup (the default), add the
following line to a file with suffix .rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-85684-9 References:
4.1.9, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-12(a), AU-12.1(ii), AU-12(c), AU-12.1(iv), AU-3, AU-3.1, MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000466-GPOS-00210, SRG-OS-000064-GPOS-00033, SLES-15-030190, SV-234918r622137_rule, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="removexattr"
KEY="perm_mod"
SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85684-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030190
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_removexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit removexattr tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85684-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030190
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_removexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for removexattr for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- removexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of removexattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- removexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of removexattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85684-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030190
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_removexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for removexattr for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- removexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of removexattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- removexattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of removexattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85684-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030190
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_removexattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Events that Modify the System's Discretionary Access Controls - setxattr
[ref]ruleAt a minimum, the audit system should collect file permission
changes for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-85687-2 References:
4.1.9, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-3, AU-3.1, AU-12(c), AU-12.1(iv), AU-12(a), AU-12.1(ii), MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SLES-15-030220, SV-234921r622137_rule, SRG-OS-000458-VMM-001810, SRG-OS-000474-VMM-001940 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="setxattr"
KEY="perm_mod"
SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85687-2
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030220
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_setxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit setxattr tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85687-2
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030220
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_setxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for setxattr for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- setxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of setxattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- setxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of setxattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85687-2
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030220
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_setxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for setxattr for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- setxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of setxattr in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- setxattr
syscall_grouping:
- fremovexattr
- lremovexattr
- removexattr
- fsetxattr
- lsetxattr
- setxattr
- name: Check existence of setxattr in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85687-2
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030220
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.5.5
- audit_rules_dac_modification_setxattr
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Events that Modify the System's Discretionary Access Controls - umount
[ref]ruleAt a minimum, the audit system should collect file system umount
changes. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S umount -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S umount -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. Identifiers:
CCE-85734-2 References:
CCI-000130, CCI-000169, CCI-000172, CCI-002884, SRG-OS-000037-GPOS-00015, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SLES-15-030360, SV-234935r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit -F arch=b32"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="umount"
KEY="perm_mod"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85734-2
- DISA-STIG-SLES-15-030360
- audit_rules_dac_modification_umount
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for umount for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- umount
syscall_grouping: []
- name: Check existence of umount in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- umount
syscall_grouping: []
- name: Check existence of umount in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85734-2
- DISA-STIG-SLES-15-030360
- audit_rules_dac_modification_umount
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Events that Modify the System's Discretionary Access Controls - umount2
[ref]ruleAt a minimum, the audit system should collect file system umount2
changes. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following line to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S umount2 -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S umount2 -F auid>=1000 -F auid!=unset -F key=perm_mod
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S umount2 -F auid>=1000 -F auid!=unset -F key=perm_mod
If the system is 64 bit then also add the following line:
-a always,exit -F arch=b64 -S umount2 -F auid>=1000 -F auid!=unset -F key=perm_mod Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:The changing of file permissions could indicate that a user is attempting to
gain access to information that would otherwise be disallowed. Auditing DAC modifications
can facilitate the identification of patterns of abuse among both authorized and
unauthorized users. References:
CCI-000130, CCI-000169, CCI-000172, CCI-002884, SRG-OS-000037-GPOS-00015, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SLES-15-030360, SV-234935r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="umount2"
KEY="perm_mod"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- DISA-STIG-SLES-15-030360
- audit_rules_dac_modification_umount2
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit umount2 tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- DISA-STIG-SLES-15-030360
- audit_rules_dac_modification_umount2
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for umount2 for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- umount2
syscall_grouping: []
- name: Check existence of umount2 in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- umount2
syscall_grouping: []
- name: Check existence of umount2 in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- DISA-STIG-SLES-15-030360
- audit_rules_dac_modification_umount2
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for umount2 for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- umount2
syscall_grouping: []
- name: Check existence of umount2 in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- umount2
syscall_grouping: []
- name: Check existence of umount2 in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- DISA-STIG-SLES-15-030360
- audit_rules_dac_modification_umount2
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Execution Attempts to Run ACL Privileged Commands
[ref]groupAt a minimum, the audit system should collect the execution of
ACL privileged commands for all users and root. |
contains 3 rules |
Record Any Attempts to Run chacl
[ref]ruleAt a minimum, the audit system should collect any execution attempt
of the chacl command for all users and root. If the auditd
daemon is configured to use the augenrules program to read audit rules
during daemon startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/usr/bin/chacl -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F path=/usr/bin/chacl -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged Rationale:Without generating audit records that are specific to the security and
mission needs of the organization, it would be difficult to establish,
correlate, and investigate the events relating to an incident or identify
those responsible for one.
Audit records can be generated from various components within the
information system (e.g., module or policy filter). Identifiers:
CCE-85595-7 References:
CCI-000130, CCI-000169, CCI-000172, CCI-002884, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SLES-15-030440, SV-234943r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/chacl -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85595-7
- DISA-STIG-SLES-15-030440
- audit_rules_execution_chacl
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /usr/bin/chacl
block:
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/chacl -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/chacl -F perm=x
-F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/chacl -F perm=x
-F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/chacl -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|")
}}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/chacl -F perm=x -F auid>=1000
-F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/chacl -F perm=x
-F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85595-7
- DISA-STIG-SLES-15-030440
- audit_rules_execution_chacl
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Record Any Attempts to Run chmod
[ref]ruleAt a minimum, the audit system should collect any execution attempt
of the chmod command for all users and root. If the auditd
daemon is configured to use the augenrules program to read audit rules
during daemon startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/usr/bin/chmod -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F path=/usr/bin/chmod -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged Rationale:Without generating audit records that are specific to the security and
mission needs of the organization, it would be difficult to establish,
correlate, and investigate the events relating to an incident or identify
those responsible for one.
Audit records can be generated from various components within the
information system (e.g., module or policy filter). Identifiers:
CCE-85593-2 References:
CCI-000130, CCI-000169, CCI-000172, CCI-002884, SRG-OS-000037-GPOS-00015, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SLES-15-030420, SV-234941r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/chmod -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85593-2
- DISA-STIG-SLES-15-030420
- audit_rules_execution_chmod
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /usr/bin/chmod
block:
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/chmod -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/chmod -F perm=x
-F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/chmod -F perm=x
-F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/chmod -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|")
}}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/chmod -F perm=x -F auid>=1000
-F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/chmod -F perm=x
-F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85593-2
- DISA-STIG-SLES-15-030420
- audit_rules_execution_chmod
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Record Any Attempts to Run setfacl
[ref]ruleAt a minimum, the audit system should collect any execution attempt
of the setfacl command for all users and root. If the auditd
daemon is configured to use the augenrules program to read audit rules
during daemon startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/usr/bin/setfacl -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F path=/usr/bin/setfacl -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged Rationale:Without generating audit records that are specific to the security and
mission needs of the organization, it would be difficult to establish,
correlate, and investigate the events relating to an incident or identify
those responsible for one.
Audit records can be generated from various components within the
information system (e.g., module or policy filter). Identifiers:
CCE-85594-0 References:
CCI-000130, CCI-000169, CCI-000172, CCI-002884, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SLES-15-030430, SV-234942r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/setfacl -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85594-0
- DISA-STIG-SLES-15-030430
- audit_rules_execution_setfacl
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /usr/bin/setfacl
block:
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/setfacl -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/setfacl -F perm=x
-F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/setfacl -F
perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/setfacl -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|")
}}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/setfacl -F perm=x -F auid>=1000
-F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/setfacl -F
perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85594-0
- DISA-STIG-SLES-15-030430
- audit_rules_execution_setfacl
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Record Execution Attempts to Run SELinux Privileged Commands
[ref]groupAt a minimum, the audit system should collect the execution of
SELinux privileged commands for all users and root. |
contains 2 rules |
Record Any Attempts to Run chcon
[ref]ruleAt a minimum, the audit system should collect any execution attempt
of the chcon command for all users and root. If the auditd
daemon is configured to use the augenrules program to read audit rules
during daemon startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/usr/bin/chcon -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F path=/usr/bin/chcon -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged Rationale:Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks,
which attempt to subvert their normal role of providing some necessary but
limited capability. As such, motivation exists to monitor these programs for
unusual activity. Identifiers:
CCE-85716-9 References:
1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-3, AU-3.1, AU-12(a), AU-12.1(ii)AU-12.1(iv), MA-4(1)(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209, SLES-15-030450, SV-234944r622137_rule, SRG-OS-000463-VMM-001850 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/chcon -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85716-9
- DISA-STIG-SLES-15-030450
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_execution_chcon
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /usr/bin/chcon
block:
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/chcon -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/chcon -F perm=x
-F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/chcon -F perm=x
-F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/chcon -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|")
}}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/chcon -F perm=x -F auid>=1000
-F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/chcon -F perm=x
-F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85716-9
- DISA-STIG-SLES-15-030450
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_execution_chcon
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Record Any Attempts to Run rm
[ref]ruleAt a minimum, the audit system should collect any execution attempt
of the rm command for all users and root. If the auditd
daemon is configured to use the augenrules program to read audit rules
during daemon startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/usr/bin/rm -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F path=/usr/bin/rm -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged Rationale:Without generating audit records that are specific to the security and
mission needs of the organization, it would be difficult to establish,
correlate, and investigate the events relating to an incident or identify
those responsible for one.
Audit records can be generated from various components within the
information system (e.g., module or policy filter). Identifiers:
CCE-85596-5 References:
CCI-000130, CCI-000169, CCI-000172, CCI-002884, SRG-OS-000037-GPOS-00015, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SLES-15-030460, SV-234945r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/rm -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85596-5
- DISA-STIG-SLES-15-030460
- audit_rules_execution_rm
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /usr/bin/rm
block:
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/rm -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/rm -F perm=x -F
auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/rm -F perm=x
-F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/rm -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|")
}}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/rm -F perm=x -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/rm -F perm=x
-F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85596-5
- DISA-STIG-SLES-15-030460
- audit_rules_execution_rm
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Record Unauthorized Access Attempts Events to Files (unsuccessful)
[ref]groupAt a minimum, the audit system should collect unauthorized file
accesses for all users and root. Note that the "-F arch=b32" lines should be
present even on a 64 bit system. These commands identify system calls for
auditing. Even if the system is 64 bit it can still execute 32 bit system
calls. Additionally, these rules can be configured in a number of ways while
still achieving the desired effect. An example of this is that the "-S" calls
could be split up and placed on separate lines, however, this is less efficient.
Add the following to /etc/audit/audit.rules :
-a always,exit -F arch=b32 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If your system is 64 bit then these lines should be duplicated and the
arch=b32 replaced with arch=b64 as follows:
-a always,exit -F arch=b64 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access |
contains 11 rules |
Record Unsuccessful Access Attempts to Files - creat
[ref]ruleAt a minimum, the audit system should collect unauthorized file
accesses for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing
these events could serve as evidence of potential system compromise. Identifiers:
CCE-85681-5 References:
4.1.10, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-3, AU-3.1, AU-12(a), AU-12.1(ii), AU-12(c), AU-12.1(iv), MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.4, Req-10.2.1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SLES-15-030160, SV-234915r622137_rule, SRG-OS-000458-VMM-001810, SRG-OS-000461-VMM-001830 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85681-5
- DISA-STIG-SLES-15-030160
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_creat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit creat tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85681-5
- DISA-STIG-SLES-15-030160
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_creat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for creat EACCES for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- creat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of creat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- creat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of creat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85681-5
- DISA-STIG-SLES-15-030160
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_creat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for creat EACCES for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- creat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of creat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- creat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of creat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85681-5
- DISA-STIG-SLES-15-030160
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_creat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for creat EPERM for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- creat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of creat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- creat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of creat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85681-5
- DISA-STIG-SLES-15-030160
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_creat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for creat EPERM for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- creat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of creat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- creat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of creat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85681-5
- DISA-STIG-SLES-15-030160
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_creat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Unsuccessful Access Attempts to Files - ftruncate
[ref]ruleAt a minimum, the audit system should collect unauthorized file
accesses for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S ftruncate -F exiu=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing
these events could serve as evidence of potential system compromise. Identifiers:
CCE-85696-3 References:
4.1.10, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-3, AU-3.1, AU-12(c), AU-12.1(iv), AU-12(a), AU-12.1(ii), MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.4, Req-10.2.1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SLES-15-030320, SV-234931r622137_rule, SRG-OS-000458-VMM-001810, SRG-OS-000461-VMM-001830 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85696-3
- DISA-STIG-SLES-15-030320
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_ftruncate
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit ftruncate tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85696-3
- DISA-STIG-SLES-15-030320
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_ftruncate
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for ftruncate EACCES for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- ftruncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of ftruncate in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- ftruncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of ftruncate in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85696-3
- DISA-STIG-SLES-15-030320
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_ftruncate
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for ftruncate EACCES for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- ftruncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of ftruncate in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- ftruncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of ftruncate in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85696-3
- DISA-STIG-SLES-15-030320
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_ftruncate
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for ftruncate EPERM for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- ftruncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of ftruncate in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- ftruncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of ftruncate in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85696-3
- DISA-STIG-SLES-15-030320
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_ftruncate
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for ftruncate EPERM for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- ftruncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of ftruncate in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- ftruncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of ftruncate in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85696-3
- DISA-STIG-SLES-15-030320
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_ftruncate
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Unsuccessful Access Attempts to Files - open
[ref]ruleAt a minimum, the audit system should collect unauthorized file
accesses for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing
these events could serve as evidence of potential system compromise. Identifiers:
CCE-85680-7 References:
4.1.10, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-12(c), AU-12.1(iv), AU-12(a), AU-12.1(ii), AU-3, AU-3.1, MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.4, Req-10.2.1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SLES-15-030150, SV-234914r622137_rule, SRG-OS-000458-VMM-001810, SRG-OS-000461-VMM-001830 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85680-7
- DISA-STIG-SLES-15-030150
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_open
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit open tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85680-7
- DISA-STIG-SLES-15-030150
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_open
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for open EACCES for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- open
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of open in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- open
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of open in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85680-7
- DISA-STIG-SLES-15-030150
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_open
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for open EACCES for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- open
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of open in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- open
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of open in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85680-7
- DISA-STIG-SLES-15-030150
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_open
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for open EPERM for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- open
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of open in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- open
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of open in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85680-7
- DISA-STIG-SLES-15-030150
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_open
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for open EPERM for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- open
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of open in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- open
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of open in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85680-7
- DISA-STIG-SLES-15-030150
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_open
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Unsuccessful Access Attempts to Files - open_by_handle_at
[ref]ruleAt a minimum, the audit system should collect unauthorized file
accesses for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing
these events could serve as evidence of potential system compromise. Identifiers:
CCE-85683-1 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-3, AU-3.1, AU-12(c), AU-12.1(iv), AU-12(a), AU-12.1(ii), MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.4, Req-10.2.1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SLES-15-030180, SV-234917r622137_rule, SRG-OS-000458-VMM-001810, SRG-OS-000461-VMM-001830 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85683-1
- DISA-STIG-SLES-15-030180
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_open_by_handle_at
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit open_by_handle_at tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85683-1
- DISA-STIG-SLES-15-030180
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_open_by_handle_at
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for open_by_handle_at EACCES for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- open_by_handle_at
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of open_by_handle_at in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- open_by_handle_at
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of open_by_handle_at in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85683-1
- DISA-STIG-SLES-15-030180
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_open_by_handle_at
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for open_by_handle_at EACCES for x86_64
platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- open_by_handle_at
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of open_by_handle_at in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- open_by_handle_at
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of open_by_handle_at in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85683-1
- DISA-STIG-SLES-15-030180
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_open_by_handle_at
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for open_by_handle_at EPERM for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- open_by_handle_at
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of open_by_handle_at in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- open_by_handle_at
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of open_by_handle_at in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85683-1
- DISA-STIG-SLES-15-030180
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_open_by_handle_at
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for open_by_handle_at EPERM for x86_64
platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- open_by_handle_at
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of open_by_handle_at in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- open_by_handle_at
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of open_by_handle_at in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85683-1
- DISA-STIG-SLES-15-030180
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_open_by_handle_at
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Unsuccessful Access Attempts to Files - openat
[ref]ruleAt a minimum, the audit system should collect unauthorized file
accesses for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing
these events could serve as evidence of potential system compromise. Identifiers:
CCE-85682-3 References:
4.1.10, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-12(a), AU-12.1(ii), AU-12(c), AU-12.1(iv), AU-3, AU-3.1, MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.4, Req-10.2.1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SLES-15-030170, SV-234916r622137_rule, SRG-OS-000458-VMM-001810, SRG-OS-000461-VMM-001830 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85682-3
- DISA-STIG-SLES-15-030170
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_openat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit openat tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85682-3
- DISA-STIG-SLES-15-030170
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_openat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for openat EACCES for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- openat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of openat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- openat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of openat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85682-3
- DISA-STIG-SLES-15-030170
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_openat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for openat EACCES for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- openat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of openat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- openat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of openat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85682-3
- DISA-STIG-SLES-15-030170
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_openat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for openat EPERM for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- openat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of openat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- openat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of openat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85682-3
- DISA-STIG-SLES-15-030170
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_openat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for openat EPERM for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- openat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of openat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- openat
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of openat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85682-3
- DISA-STIG-SLES-15-030170
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_openat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Unsuccessul Delete Attempts to Files - rename
[ref]ruleThe audit system should collect unsuccessful file deletion
attempts for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d .
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file.
-a always,exit -F arch=b32 -S rename -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccessful-delete
-a always,exit -F arch=b32 -S rename -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccessful-delete
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S rename -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccessful-delete
-a always,exit -F arch=b64 -S rename -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccessful-delete Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping system calls related
to the same event is more efficient. See the following example:
-a always,exit -F arch=b32 -S unlink,unlinkat,rename,renameat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-delete Rationale:Unsuccessful attempts to delete files could be an indicator of malicious activity on a system. Auditing
these events could serve as evidence of potential system compromise. Identifiers:
CCE-85701-1 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-12(c), AU-12.1(iv), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.4, Req-10.2.1, SRG-OS-000064-GPOS-00033, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SRG-OS-000468-GPOS-00212, SLES-15-030710, SV-234970r622137_rule, SRG-OS-000458-VMM-001810, SRG-OS-000461-VMM-001830 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85701-1
- DISA-STIG-SLES-15-030710
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_rename
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit rename tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85701-1
- DISA-STIG-SLES-15-030710
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_rename
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for rename EACCES for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- rename
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of rename in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- rename
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of rename in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85701-1
- DISA-STIG-SLES-15-030710
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_rename
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for rename EACCES for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- rename
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of rename in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- rename
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of rename in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85701-1
- DISA-STIG-SLES-15-030710
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_rename
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for rename EPERM for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- rename
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of rename in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- rename
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of rename in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85701-1
- DISA-STIG-SLES-15-030710
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_rename
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for rename EPERM for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- rename
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of rename in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- rename
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of rename in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85701-1
- DISA-STIG-SLES-15-030710
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_rename
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Unsuccessul Delete Attempts to Files - renameat
[ref]ruleThe audit system should collect unsuccessful file deletion
attempts for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d .
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file.
-a always,exit -F arch=b32 -S renameat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccessful-delete
-a always,exit -F arch=b32 -S renameat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccessful-delete
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S renameat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccessful-delete
-a always,exit -F arch=b64 -S renameat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccessful-delete Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping system calls related
to the same event is more efficient. See the following example:
-a always,exit -F arch=b32 -S unlink,unlinkat,rename,renameat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-delete Rationale:Unsuccessful attempts to delete files could be an indicator of malicious activity on a system. Auditing
these events could serve as evidence of potential system compromise. Identifiers:
CCE-85702-9 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-12(c), AU-12.1(iv), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.4, Req-10.2.1, SRG-OS-000064-GPOS-00033, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SRG-OS-000468-GPOS-00212, SLES-15-030720, SV-234971r622137_rule, SRG-OS-000458-VMM-001810, SRG-OS-000461-VMM-001830 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85702-9
- DISA-STIG-SLES-15-030720
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_renameat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit renameat tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85702-9
- DISA-STIG-SLES-15-030720
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_renameat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for renameat EACCES for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- renameat
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of renameat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- renameat
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of renameat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85702-9
- DISA-STIG-SLES-15-030720
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_renameat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for renameat EACCES for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- renameat
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of renameat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- renameat
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of renameat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85702-9
- DISA-STIG-SLES-15-030720
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_renameat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for renameat EPERM for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- renameat
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of renameat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- renameat
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of renameat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85702-9
- DISA-STIG-SLES-15-030720
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_renameat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for renameat EPERM for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- renameat
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of renameat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- renameat
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of renameat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85702-9
- DISA-STIG-SLES-15-030720
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_renameat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Unsuccessul Delete Attempts to Files - renameat2
[ref]ruleThe audit system should collect unsuccessful file deletion
attempts for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d .
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file.
-a always,exit -F arch=b32 -S renameat2 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccessful-delete
-a always,exit -F arch=b32 -S renameat2 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccessful-delete
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S renameat2 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccessful-delete
-a always,exit -F arch=b64 -S renameat2 -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccessful-delete Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping system calls related
to the same event is more efficient. See the following example:
-a always,exit -F arch=b32 -S unlink,unlinkat,rename,renameat,renameat2 -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-delete Rationale:Unsuccessful attempts to delete files could be an indicator of malicious activity on a system. Auditing
these events could serve as evidence of potential system compromise. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85726-8
- DISA-STIG-SLES-15-030730
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_unsuccessful_file_modification_renameat2
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit renameat2 tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85726-8
- DISA-STIG-SLES-15-030730
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_unsuccessful_file_modification_renameat2
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for renameat2 EACCES for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- renameat2
syscall_grouping:
- rename
- renameat
- renameat2
- unlink
- unlinkat
- name: Check existence of renameat2 in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- renameat2
syscall_grouping:
- rename
- renameat
- renameat2
- unlink
- unlinkat
- name: Check existence of renameat2 in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85726-8
- DISA-STIG-SLES-15-030730
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_unsuccessful_file_modification_renameat2
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for renameat2 EACCES for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- renameat2
syscall_grouping:
- rename
- renameat
- renameat2
- unlink
- unlinkat
- name: Check existence of renameat2 in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- renameat2
syscall_grouping:
- rename
- renameat
- renameat2
- unlink
- unlinkat
- name: Check existence of renameat2 in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85726-8
- DISA-STIG-SLES-15-030730
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_unsuccessful_file_modification_renameat2
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for renameat2 EPERM for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- renameat2
syscall_grouping:
- rename
- renameat
- renameat2
- unlink
- unlinkat
- name: Check existence of renameat2 in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- renameat2
syscall_grouping:
- rename
- renameat
- renameat2
- unlink
- unlinkat
- name: Check existence of renameat2 in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85726-8
- DISA-STIG-SLES-15-030730
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_unsuccessful_file_modification_renameat2
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for renameat2 EPERM for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- renameat2
syscall_grouping:
- rename
- renameat
- renameat2
- unlink
- unlinkat
- name: Check existence of renameat2 in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- renameat2
syscall_grouping:
- rename
- renameat
- renameat2
- unlink
- unlinkat
- name: Check existence of renameat2 in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85726-8
- DISA-STIG-SLES-15-030730
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_unsuccessful_file_modification_renameat2
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Unsuccessful Access Attempts to Files - truncate
[ref]ruleAt a minimum, the audit system should collect unauthorized file
accesses for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F arch=b32 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F arch=b32 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping these system
calls with others as identifying earlier in this guide is more efficient. Rationale:Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing
these events could serve as evidence of potential system compromise. Identifiers:
CCE-85608-8 References:
4.1.10, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.4, Req-10.2.1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SLES-15-030610, SV-234960r622137_rule, SRG-OS-000458-VMM-001810, SRG-OS-000461-VMM-001830 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85608-8
- DISA-STIG-SLES-15-030610
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_truncate
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit truncate tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85608-8
- DISA-STIG-SLES-15-030610
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_truncate
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for truncate EACCES for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- truncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of truncate in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- truncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of truncate in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85608-8
- DISA-STIG-SLES-15-030610
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_truncate
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for truncate EACCES for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- truncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of truncate in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- truncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of truncate in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85608-8
- DISA-STIG-SLES-15-030610
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_truncate
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for truncate EPERM for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- truncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of truncate in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- truncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of truncate in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85608-8
- DISA-STIG-SLES-15-030610
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_truncate
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for truncate EPERM for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- truncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of truncate in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- truncate
syscall_grouping:
- creat
- ftruncate
- truncate
- open
- openat
- open_by_handle_at
- name: Check existence of truncate in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85608-8
- DISA-STIG-SLES-15-030610
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_truncate
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Unsuccessul Delete Attempts to Files - unlink
[ref]ruleThe audit system should collect unsuccessful file deletion
attempts for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d .
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file.
-a always,exit -F arch=b32 -S unlink -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccessful-delete
-a always,exit -F arch=b32 -S unlink -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccessful-delete
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S unlink -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccessful-delete
-a always,exit -F arch=b64 -S unlink -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccessful-delete Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping system calls related
to the same event is more efficient. See the following example:
-a always,exit -F arch=b32 -S unlink,unlinkat,rename,renameat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-delete Rationale:Unsuccessful attempts to delete files could be an indicator of malicious activity on a system. Auditing
these events could serve as evidence of potential system compromise. Identifiers:
CCE-85703-7 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-12(c), AU-12.1(iv), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.4, Req-10.2.1, SRG-OS-000064-GPOS-00033, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SRG-OS-000468-GPOS-00212, SLES-15-030740, SV-234973r622137_rule, SRG-OS-000458-VMM-001810, SRG-OS-000461-VMM-001830 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85703-7
- DISA-STIG-SLES-15-030740
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_unlink
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit unlink tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85703-7
- DISA-STIG-SLES-15-030740
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_unlink
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for unlink EACCES for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- unlink
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of unlink in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- unlink
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of unlink in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85703-7
- DISA-STIG-SLES-15-030740
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_unlink
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for unlink EACCES for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- unlink
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of unlink in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- unlink
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of unlink in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85703-7
- DISA-STIG-SLES-15-030740
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_unlink
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for unlink EPERM for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- unlink
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of unlink in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- unlink
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of unlink in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85703-7
- DISA-STIG-SLES-15-030740
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_unlink
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for unlink EPERM for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- unlink
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of unlink in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- unlink
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of unlink in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85703-7
- DISA-STIG-SLES-15-030740
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_unlink
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Unsuccessul Delete Attempts to Files - unlinkat
[ref]ruleThe audit system should collect unsuccessful file deletion
attempts for all users and root. If the auditd daemon is configured
to use the augenrules program to read audit rules during daemon
startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d .
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file.
-a always,exit -F arch=b32 -S unlinkat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccessful-delete
-a always,exit -F arch=b32 -S unlinkat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccessful-delete
If the system is 64 bit then also add the following lines:
-a always,exit -F arch=b64 -S unlinkat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccessful-delete
-a always,exit -F arch=b64 -S unlinkat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=unsuccessful-delete Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Here the system calls
have been placed independent of other system calls. Grouping system calls related
to the same event is more efficient. See the following example:
-a always,exit -F arch=b32 -S unlink,unlinkat,rename,renameat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=unsuccesful-delete Rationale:Unsuccessful attempts to delete files could be an indicator of malicious activity on a system. Auditing
these events could serve as evidence of potential system compromise. Identifiers:
CCE-85704-5 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-12(c), AU-12.1(iv), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.4, Req-10.2.1, SRG-OS-000064-GPOS-00033, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SRG-OS-000468-GPOS-00212, SLES-15-030750, SV-234974r622137_rule, SRG-OS-000458-VMM-001810, SRG-OS-000461-VMM-001830 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85704-5
- DISA-STIG-SLES-15-030750
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_unlinkat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit unlinkat tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85704-5
- DISA-STIG-SLES-15-030750
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_unlinkat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for unlinkat EACCES for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- unlinkat
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of unlinkat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- unlinkat
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of unlinkat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85704-5
- DISA-STIG-SLES-15-030750
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_unlinkat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for unlinkat EACCES for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- unlinkat
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of unlinkat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- unlinkat
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of unlinkat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85704-5
- DISA-STIG-SLES-15-030750
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_unlinkat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for unlinkat EPERM for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- unlinkat
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of unlinkat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- unlinkat
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of unlinkat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85704-5
- DISA-STIG-SLES-15-030750
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_unlinkat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for unlinkat EPERM for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- unlinkat
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of unlinkat in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
set_fact: audit_file="/etc/audit/rules.d/access.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- unlinkat
syscall_grouping:
- rename
- renameat
- unlink
- unlinkat
- name: Check existence of unlinkat in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
(?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
-F auid>=1000 -F auid!=unset -F key=access
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85704-5
- DISA-STIG-SLES-15-030750
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.1
- PCI-DSS-Req-10.2.4
- audit_rules_unsuccessful_file_modification_unlinkat
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Information on Kernel Modules Loading and Unloading
[ref]groupTo capture kernel module loading and unloading events, use following lines, setting ARCH to
either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:
-a always,exit -F arch=ARCH -S init_module,delete_module -F key=modules
Place to add the lines depends on a way auditd daemon is configured. If it is configured
to use the augenrules program (the default), add the lines to a file with suffix
.rules in the directory /etc/audit/rules.d .
If the auditd daemon is configured to use the auditctl utility,
add the lines to file /etc/audit/audit.rules . |
contains 3 rules |
Ensure auditd Collects Information on Kernel Module Unloading - delete_module
[ref]ruleTo capture kernel module unloading events, use following line, setting ARCH to
either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:
-a always,exit -F arch=ARCH -S delete_module -F key=modules
Place to add the line depends on a way auditd daemon is configured. If it is configured
to use the augenrules program (the default), add the line to a file with suffix
.rules in the directory /etc/audit/rules.d .
If the auditd daemon is configured to use the auditctl utility,
add the line to file /etc/audit/audit.rules .Rationale:The removal of kernel modules can be used to alter the behavior of
the kernel and potentially introduce malicious code into kernel space. It is important
to have an audit trail of modules that have been introduced into the kernel. Identifiers:
CCE-85748-2 References:
4.1.16, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-3, AU-3.1, AU-12(a), AU-12.1(ii), AU-12.1(iv), MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000471-GPOS-00216, SRG-OS-000477-GPOS-00222, SLES-15-030520, SV-234951r622137_rule, SRG-OS-000477-VMM-001970 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
# Note: 32-bit and 64-bit kernel syscall numbers not always line up =>
# it's required on a 64-bit system to check also for the presence
# of 32-bit's equivalent of the corresponding rule.
# (See `man 7 audit.rules` for details )
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS=""
SYSCALL="delete_module"
KEY="modules"
SYSCALL_GROUPING="delete_module"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85748-2
- DISA-STIG-SLES-15-030520
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.7
- audit_rules_kernel_module_loading_delete
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set architecture for audit delete_module tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85748-2
- DISA-STIG-SLES-15-030520
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.7
- audit_rules_kernel_module_loading_delete
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Perform remediation of Audit rules for delete_module for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- delete_module
syscall_grouping: []
- name: Check existence of delete_module in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/module-change.rules
set_fact: audit_file="/etc/audit/rules.d/module-change.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=module-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- delete_module
syscall_grouping: []
- name: Check existence of delete_module in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=module-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85748-2
- DISA-STIG-SLES-15-030520
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.7
- audit_rules_kernel_module_loading_delete
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Perform remediation of Audit rules for delete_module for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- delete_module
syscall_grouping: []
- name: Check existence of delete_module in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/module-change.rules
set_fact: audit_file="/etc/audit/rules.d/module-change.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=module-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- delete_module
syscall_grouping: []
- name: Check existence of delete_module in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=module-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85748-2
- DISA-STIG-SLES-15-030520
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.7
- audit_rules_kernel_module_loading_delete
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
|
Ensure auditd Collects Information on Kernel Module Loading and Unloading - finit_module
[ref]ruleIf the auditd daemon is configured to use the augenrules program
to read audit rules during daemon startup (the default), add the following lines to a file
with suffix .rules in the directory /etc/audit/rules.d to capture kernel module
loading and unloading events, setting ARCH to either b32 or b64 as appropriate for your system:
-a always,exit -F arch=ARCH -S finit_module -F key=modules
If the auditd daemon is configured to use the auditctl utility to read audit
rules during daemon startup, add the following lines to /etc/audit/audit.rules file
in order to capture kernel module loading and unloading events, setting ARCH to either b32 or
b64 as appropriate for your system:
-a always,exit -F arch=ARCH -S finit_module -F key=modules Rationale:The addition/removal of kernel modules can be used to alter the behavior of
the kernel and potentially introduce malicious code into kernel space. It is important
to have an audit trail of modules that have been introduced into the kernel. Identifiers:
CCE-85749-0 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-3, AU-3.1, AU-12(a), AU-12.1(ii), AU-12.1(iv), MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000471-GPOS-00216, SRG-OS-000477-GPOS-00222, SLES-15-030530, SV-234952r622137_rule, SRG-OS-000477-VMM-001970 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
# Note: 32-bit and 64-bit kernel syscall numbers not always line up =>
# it's required on a 64-bit system to check also for the presence
# of 32-bit's equivalent of the corresponding rule.
# (See `man 7 audit.rules` for details )
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS=""
SYSCALL="finit_module"
KEY="modules"
SYSCALL_GROUPING="init_module finit_module"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85749-0
- DISA-STIG-SLES-15-030530
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.7
- audit_rules_kernel_module_loading_finit
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set architecture for audit finit_module tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85749-0
- DISA-STIG-SLES-15-030530
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.7
- audit_rules_kernel_module_loading_finit
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Perform remediation of Audit rules for finit_module for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- finit_module
syscall_grouping:
- init_module
- finit_module
- name: Check existence of finit_module in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/module-change.rules
set_fact: audit_file="/etc/audit/rules.d/module-change.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=module-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- finit_module
syscall_grouping:
- init_module
- finit_module
- name: Check existence of finit_module in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=module-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85749-0
- DISA-STIG-SLES-15-030530
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.7
- audit_rules_kernel_module_loading_finit
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Perform remediation of Audit rules for finit_module for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- finit_module
syscall_grouping:
- init_module
- finit_module
- name: Check existence of finit_module in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/module-change.rules
set_fact: audit_file="/etc/audit/rules.d/module-change.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=module-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- finit_module
syscall_grouping:
- init_module
- finit_module
- name: Check existence of finit_module in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=module-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85749-0
- DISA-STIG-SLES-15-030530
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.7
- audit_rules_kernel_module_loading_finit
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
|
Ensure auditd Collects Information on Kernel Module Loading - init_module
[ref]ruleTo capture kernel module loading events, use following line, setting ARCH to
either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:
-a always,exit -F arch=ARCH -S init_module -F key=modules
Place to add the line depends on a way auditd daemon is configured. If it is configured
to use the augenrules program (the default), add the line to a file with suffix
.rules in the directory /etc/audit/rules.d .
If the auditd daemon is configured to use the auditctl utility,
add the line to file /etc/audit/audit.rules .Rationale:The addition of kernel modules can be used to alter the behavior of
the kernel and potentially introduce malicious code into kernel space. It is important
to have an audit trail of modules that have been introduced into the kernel. Identifiers:
CCE-85750-8 References:
4.1.16, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-3, AU-3.1, AU-12(a), AU-12.1(ii), AU-12.1(iv), MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000471-GPOS-00216, SRG-OS-000477-GPOS-00222, SLES-15-030540, SV-234953r622137_rule, SRG-OS-000477-VMM-001970 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
# Note: 32-bit and 64-bit kernel syscall numbers not always line up =>
# it's required on a 64-bit system to check also for the presence
# of 32-bit's equivalent of the corresponding rule.
# (See `man 7 audit.rules` for details )
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS=""
SYSCALL="init_module"
KEY="modules"
SYSCALL_GROUPING="init_module finit_module"
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85750-8
- DISA-STIG-SLES-15-030540
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.7
- audit_rules_kernel_module_loading_init
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set architecture for audit init_module tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85750-8
- DISA-STIG-SLES-15-030540
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.7
- audit_rules_kernel_module_loading_init
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Perform remediation of Audit rules for init_module for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- init_module
syscall_grouping:
- init_module
- finit_module
- name: Check existence of init_module in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/module-change.rules
set_fact: audit_file="/etc/audit/rules.d/module-change.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=module-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- init_module
syscall_grouping:
- init_module
- finit_module
- name: Check existence of init_module in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=module-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85750-8
- DISA-STIG-SLES-15-030540
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.7
- audit_rules_kernel_module_loading_init
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Perform remediation of Audit rules for init_module for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- init_module
syscall_grouping:
- init_module
- finit_module
- name: Check existence of init_module in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/module-change.rules
set_fact: audit_file="/etc/audit/rules.d/module-change.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=module-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- init_module
syscall_grouping:
- init_module
- finit_module
- name: Check existence of init_module in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=module-change
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85750-8
- DISA-STIG-SLES-15-030540
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.7
- audit_rules_kernel_module_loading_init
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
|
Record Attempts to Alter Logon and Logout Events
[ref]groupThe audit system already collects login information for all users
and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d in order to watch for attempted manual
edits of files involved in storing logon events:
-w /var/log/tallylog -p wa -k logins
-w /var/run/faillock/ -p wa -k logins
-w /var/log/lastlog -p wa -k logins
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file in order to watch for unattempted manual
edits of files involved in storing logon events:
-w /var/log/tallylog -p wa -k logins
-w /var/run/faillock/ -p wa -k logins
-w /var/log/lastlog -p wa -k logins |
contains 2 rules |
Record Attempts to Alter Logon and Logout Events - lastlog
[ref]ruleThe audit system already collects login information for all users
and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d in order to watch for attempted manual
edits of files involved in storing logon events:
-w /var/log/lastlog -p wa -k logins
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file in order to watch for unattempted manual
edits of files involved in storing logon events:
-w /var/log/lastlog -p wa -k logins Rationale:Manual editing of these files may indicate nefarious activity, such
as an attacker attempting to remove evidence of an intrusion. Identifiers:
CCE-85598-1 References:
4.1.7, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.3, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000473-GPOS-00218, SRG-OS-000470-GPOS-00214, SLES-15-030480, SV-234947r622137_rule, SRG-OS-000473-VMM-001930, SRG-OS-000470-VMM-001900 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85598-1
- DISA-STIG-SLES-15-030480
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_lastlog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other user/group modification audit rules
find:
paths: /etc/audit/rules.d
recurse: false
contains: -k logins$
patterns: '*.rules'
register: find_lastlog
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85598-1
- DISA-STIG-SLES-15-030480
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_lastlog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: If existing user/group modification ruleset not found, use /etc/audit/rules.d/logins.rules
as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/logins.rules
when:
- '"audit" in ansible_facts.packages'
- find_lastlog.matched is defined and find_lastlog.matched == 0
tags:
- CCE-85598-1
- DISA-STIG-SLES-15-030480
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_lastlog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_lastlog.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_lastlog.matched is defined and find_lastlog.matched > 0
tags:
- CCE-85598-1
- DISA-STIG-SLES-15-030480
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_lastlog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the lastlog rule in rules.d when on x86
lineinfile:
path: '{{ all_files[0] }}'
line: -w /var/log/lastlog -p wa -k logins
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85598-1
- DISA-STIG-SLES-15-030480
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_lastlog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the lastlog rule in /etc/audit/audit.rules
lineinfile:
line: -w /var/log/lastlog -p wa -k logins
state: present
dest: /etc/audit/audit.rules
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85598-1
- DISA-STIG-SLES-15-030480
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_lastlog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Attempts to Alter Logon and Logout Events - tallylog
[ref]ruleThe audit system already collects login information for all users
and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d in order to watch for attempted manual
edits of files involved in storing logon events:
-w /var/log/tallylog -p wa -k logins
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file in order to watch for unattempted manual
edits of files involved in storing logon events:
-w /var/log/tallylog -p wa -k logins Rationale:Manual editing of these files may indicate nefarious activity, such
as an attacker attempting to remove evidence of an intrusion. Identifiers:
CCE-85597-3 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, CCI-002884, CCI-000126, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.3, SRG-OS-000392-GPOS-00172, SRG-OS-000470-GPOS-00214, SRG-OS-000473-GPOS-00218, SLES-15-030470, SV-234946r622137_rule, SRG-OS-000473-VMM-001930, SRG-OS-000470-VMM-001900 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85597-3
- DISA-STIG-SLES-15-030470
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_tallylog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other user/group modification audit rules
find:
paths: /etc/audit/rules.d
recurse: false
contains: -k logins$
patterns: '*.rules'
register: find_tallylog
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85597-3
- DISA-STIG-SLES-15-030470
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_tallylog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: If existing user/group modification ruleset not found, use /etc/audit/rules.d/logins.rules
as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/logins.rules
when:
- '"audit" in ansible_facts.packages'
- find_tallylog.matched is defined and find_tallylog.matched == 0
tags:
- CCE-85597-3
- DISA-STIG-SLES-15-030470
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_tallylog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_tallylog.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_tallylog.matched is defined and find_tallylog.matched > 0
tags:
- CCE-85597-3
- DISA-STIG-SLES-15-030470
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_tallylog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the tallylog rule in rules.d when on x86
lineinfile:
path: '{{ all_files[0] }}'
line: -w /var/log/tallylog -p wa -k logins
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85597-3
- DISA-STIG-SLES-15-030470
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_tallylog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the tallylog rule in /etc/audit/audit.rules
lineinfile:
line: -w /var/log/tallylog -p wa -k logins
state: present
dest: /etc/audit/audit.rules
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85597-3
- DISA-STIG-SLES-15-030470
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.3
- audit_rules_login_events_tallylog
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Information on the Use of Privileged Commands
[ref]groupAt a minimum, the audit system should collect the execution of
privileged commands for all users and root. |
contains 21 rules |
Ensure auditd Collects Information on the Use of Privileged Commands - chage
[ref]ruleAt a minimum, the audit system should collect the execution of
privileged commands for all users and root. If the auditd daemon is
configured to use the augenrules program to read audit rules during
daemon startup (the default), add a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/usr/bin/chage -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add a line of the following
form to /etc/audit/audit.rules :
-a always,exit -F path=/usr/bin/chage -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged Rationale:Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks,
which attempt to subvert their normal role of providing some necessary but
limited capability. As such, motivation exists to monitor these programs for
unusual activity. Identifiers:
CCE-85587-4 References:
1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, CIP-004-3 R2.2.2, CIP-004-3 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SLES-15-030120, SV-234911r622137_rule, SRG-OS-000471-VMM-001910 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/chage -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85587-4
- DISA-STIG-SLES-15-030120
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_privileged_commands_chage
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /usr/bin/chage
block:
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/chage -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/chage -F perm=x
-F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/chage -F perm=x
-F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/chage -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|")
}}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/chage -F perm=x -F auid>=1000
-F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/chage -F perm=x
-F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85587-4
- DISA-STIG-SLES-15-030120
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_privileged_commands_chage
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure auditd Collects Information on the Use of Privileged Commands - chfn
[ref]ruleAt a minimum, the audit system should collect the execution of
privileged commands for all users and root. If the auditd daemon is
configured to use the augenrules program to read audit rules during
daemon startup (the default), add a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/usr/bin/chfn -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add a line of the following
form to /etc/audit/audit.rules :
-a always,exit -F path=/usr/bin/chfn -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged Rationale:Without generating audit records that are specific to the security and
mission needs of the organization, it would be difficult to establish,
correlate, and investigate the events relating to an incident or identify
those responsible for one.
Audit records can be generated from various components within the
information system (e.g., module or policy filter). Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/chfn -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85589-0
- DISA-STIG-SLES-15-030340
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-3
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_chfn
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /usr/bin/chfn
block:
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/chfn -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/chfn -F perm=x -F
auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/chfn -F perm=x
-F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/chfn -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|")
}}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/chfn -F perm=x -F auid>=1000
-F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/chfn -F perm=x
-F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85589-0
- DISA-STIG-SLES-15-030340
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-3
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_chfn
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure auditd Collects Information on the Use of Privileged Commands - chsh
[ref]ruleAt a minimum, the audit system should collect the execution of
privileged commands for all users and root. If the auditd daemon is
configured to use the augenrules program to read audit rules during
daemon startup (the default), add a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/usr/bin/chsh -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add a line of the following
form to /etc/audit/audit.rules :
-a always,exit -F path=/usr/bin/chsh -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged Rationale:Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks,
which attempt to subvert their normal role of providing some necessary but
limited capability. As such, motivation exists to monitor these programs for
unusual activity. Identifiers:
CCE-85586-6 References:
1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, CIP-004-3 R2.2.2, CIP-004-3 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SLES-15-030100, SV-234909r622137_rule, SRG-OS-000471-VMM-001910 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/chsh -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85586-6
- DISA-STIG-SLES-15-030100
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_privileged_commands_chsh
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /usr/bin/chsh
block:
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/chsh -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/chsh -F perm=x -F
auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/chsh -F perm=x
-F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/chsh -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|")
}}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/chsh -F perm=x -F auid>=1000
-F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/chsh -F perm=x
-F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85586-6
- DISA-STIG-SLES-15-030100
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_privileged_commands_chsh
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure auditd Collects Information on the Use of Privileged Commands - crontab
[ref]ruleAt a minimum, the audit system should collect the execution of
privileged commands for all users and root. If the auditd daemon is
configured to use the augenrules program to read audit rules during
daemon startup (the default), add a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/usr/bin/crontab -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add a line of the following
form to /etc/audit/audit.rules :
-a always,exit -F path=/usr/bin/crontab -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged Rationale:Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks,
which attempt to subvert their normal role of providing some necessary but
limited capability. As such, motivation exists to monitor these programs for
unusual activity. Identifiers:
CCE-85588-2 References:
1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SLES-15-030130, SV-234912r622137_rule, SRG-OS-000471-VMM-001910 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/crontab -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85588-2
- DISA-STIG-SLES-15-030130
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_privileged_commands_crontab
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /usr/bin/crontab
block:
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/crontab -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/crontab -F perm=x
-F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/crontab -F
perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/crontab -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|")
}}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/crontab -F perm=x -F auid>=1000
-F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/crontab -F
perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85588-2
- DISA-STIG-SLES-15-030130
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_privileged_commands_crontab
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure auditd Collects Information on the Use of Privileged Commands - gpasswd
[ref]ruleAt a minimum, the audit system should collect the execution of
privileged commands for all users and root. If the auditd daemon is
configured to use the augenrules program to read audit rules during
daemon startup (the default), add a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/usr/bin/gpasswd -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add a line of the following
form to /etc/audit/audit.rules :
-a always,exit -F path=/usr/bin/gpasswd -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged Rationale:Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks,
which attempt to subvert their normal role of providing some necessary but
limited capability. As such, motivation exists to monitor these programs for
unusual activity. Identifiers:
CCE-85584-1 References:
1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, CIP-004-3 R2.2.2, CIP-004-3 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SLES-15-030080, SV-234907r622137_rule, SRG-OS-000471-VMM-001910 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/gpasswd -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85584-1
- DISA-STIG-SLES-15-030080
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_privileged_commands_gpasswd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /usr/bin/gpasswd
block:
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/gpasswd -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/gpasswd -F perm=x
-F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/gpasswd -F
perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/gpasswd -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|")
}}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/gpasswd -F perm=x -F auid>=1000
-F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/gpasswd -F
perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85584-1
- DISA-STIG-SLES-15-030080
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_privileged_commands_gpasswd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure auditd Collects Information on the Use of Privileged Commands - insmod
[ref]ruleAt a minimum, the audit system should collect the execution of
privileged commands for all users and root. If the auditd daemon is
configured to use the augenrules program to read audit rules during
daemon startup (the default), add a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d :
-w /sbin/insmod -p x -k modules Rationale:Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks,
which attempt to subvert their normal role of providing some necessary but
limited capability. As such, motivation exists to monitor these programs for
unusual activity. Identifiers:
CCE-85744-1 References:
4.1.16, CCI-000130, CCI-000169, CCI-000172, CCI-002884, AU-12(c), AU-12.1(iv), AU-3, AU-3.1, AU-12(a), AU-12.1(ii), MA-4(1)(a), SRG-OS-000037-GPOS-00015, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SLES-15-030380, SV-234937r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/sbin/insmod" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/sbin/insmod $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "x" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/sbin/insmod$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /sbin/insmod -p x -k modules" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/modules.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/sbin/insmod" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/modules.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/modules.rules"
# If the modules.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/sbin/insmod" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/sbin/insmod $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "x" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/sbin/insmod$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /sbin/insmod -p x -k modules" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85744-1
- DISA-STIG-SLES-15-030380
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_insmod
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /sbin/insmod already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/sbin/insmod\s+-p\s+x(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85744-1
- DISA-STIG-SLES-15-030380
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_insmod
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key modules
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)modules$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85744-1
- DISA-STIG-SLES-15-030380
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_insmod
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use /etc/audit/rules.d/modules.rules as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/modules.rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85744-1
- DISA-STIG-SLES-15-030380
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_insmod
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85744-1
- DISA-STIG-SLES-15-030380
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_insmod
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /sbin/insmod in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /sbin/insmod -p x -k modules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85744-1
- DISA-STIG-SLES-15-030380
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_insmod
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /sbin/insmod already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/sbin/insmod\s+-p\s+x(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85744-1
- DISA-STIG-SLES-15-030380
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_insmod
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /sbin/insmod in /etc/audit/audit.rules
lineinfile:
line: -w /sbin/insmod -p x -k modules
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-85744-1
- DISA-STIG-SLES-15-030380
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_insmod
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure auditd Collects Information on the Use of Privileged Commands - kmod
[ref]ruleAt a minimum, the audit system should collect the execution of
privileged commands for all users and root. If the auditd daemon is
configured to use the augenrules program to read audit rules during
daemon startup (the default), add a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d :
-w /usr/bin/kmod -p x -k modules
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add a line of the following
form to /etc/audit/audit.rules :
-w /usr/bin/kmod -p x -k modules Rationale:Without generating audit records that are specific to the security and
mission needs of the organization, it would be difficult to establish,
correlate, and investigate the events relating to an incident or identify
those responsible for one.
Audit records can be generated from various components within the
information system (e.g., module or policy filter). Identifiers:
CCE-85591-6 References:
CCI-000130, CCI-000169, CCI-000172, CCI-002884, AU-3, AU-3.1, AU-12(a), AU-12.1(ii), AU-12.1(iv)AU-12(c), MA-4(1)(a), SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000471-GPOS-00216, SRG-OS-000477-GPOS-00222, SLES-15-030410, SV-234940r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/kmod -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85591-6
- DISA-STIG-SLES-15-030410
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)AU-12(c)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_kmod
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Service facts
service_facts: null
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85591-6
- DISA-STIG-SLES-15-030410
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)AU-12(c)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_kmod
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check the rules script being used
command: grep '^ExecStartPost' /usr/lib/systemd/system/auditd.service
register: check_rules_scripts_result
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85591-6
- DISA-STIG-SLES-15-030410
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)AU-12(c)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_kmod
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Update kmod in /etc/audit/rules.d/audit.rules
lineinfile:
path: /etc/audit/rules.d/audit.rules
line: -w /usr/bin/kmod -p x -k modules
create: true
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"auditd.service" in ansible_facts.services'
- '"augenrules" in check_rules_scripts_result.stdout'
register: augenrules_audit_rules_kmod_update_result
tags:
- CCE-85591-6
- DISA-STIG-SLES-15-030410
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)AU-12(c)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_kmod
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Update kmod in /etc/audit/audit.rules
lineinfile:
path: /etc/audit/audit.rules
line: -w /usr/bin/kmod -p x -k modules
create: true
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"auditd.service" in ansible_facts.services'
- '"auditctl" in check_rules_scripts_result.stdout'
register: auditctl_audit_rules_kmod_update_result
tags:
- CCE-85591-6
- DISA-STIG-SLES-15-030410
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)AU-12(c)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_kmod
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Restart auditd.service
systemd:
name: auditd.service
state: restarted
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- (augenrules_audit_rules_kmod_update_result.changed or auditctl_audit_rules_kmod_update_result.changed)
- ansible_facts.services["auditd.service"].state == "running"
tags:
- CCE-85591-6
- DISA-STIG-SLES-15-030410
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)AU-12(c)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_kmod
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure auditd Collects Information on the Use of Privileged Commands - modprobe
[ref]ruleAt a minimum, the audit system should collect the execution of
privileged commands for all users and root. If the auditd daemon is
configured to use the augenrules program to read audit rules during
daemon startup (the default), add a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d :
-w /sbin/modprobe -p x -k modules
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add a line of the following
form to /etc/audit/audit.rules :
-w /sbin/modprobe -p x -k modules Rationale:Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks,
which attempt to subvert their normal role of providing some necessary but
limited capability. As such, motivation exists to monitor these programs for
unusual activity. Identifiers:
CCE-85731-8 References:
4.1.16, CCI-000130, CCI-000169, CCI-000172, CCI-002884, AU-12(a), AU-12.1(ii), AU-3, AU-3.1, AU-12(c), AU-12.1(iv), MA-4(1)(a), SRG-OS-000037-GPOS-00015, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SLES-15-030400, SV-234939r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/sbin/modprobe" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/sbin/modprobe $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "x" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/sbin/modprobe$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /sbin/modprobe -p x -k modules" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/modules.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/sbin/modprobe" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/modules.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/modules.rules"
# If the modules.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/sbin/modprobe" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/sbin/modprobe $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "x" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/sbin/modprobe$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /sbin/modprobe -p x -k modules" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85731-8
- DISA-STIG-SLES-15-030400
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_modprobe
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /sbin/modprobe already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/sbin/modprobe\s+-p\s+x(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85731-8
- DISA-STIG-SLES-15-030400
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_modprobe
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key modules
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)modules$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85731-8
- DISA-STIG-SLES-15-030400
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_modprobe
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use /etc/audit/rules.d/modules.rules as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/modules.rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85731-8
- DISA-STIG-SLES-15-030400
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_modprobe
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85731-8
- DISA-STIG-SLES-15-030400
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_modprobe
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /sbin/modprobe in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /sbin/modprobe -p x -k modules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85731-8
- DISA-STIG-SLES-15-030400
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_modprobe
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /sbin/modprobe already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/sbin/modprobe\s+-p\s+x(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85731-8
- DISA-STIG-SLES-15-030400
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_modprobe
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /sbin/modprobe in /etc/audit/audit.rules
lineinfile:
line: -w /sbin/modprobe -p x -k modules
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-85731-8
- DISA-STIG-SLES-15-030400
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_modprobe
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure auditd Collects Information on the Use of Privileged Commands - newgrp
[ref]ruleAt a minimum, the audit system should collect the execution of
privileged commands for all users and root. If the auditd daemon is
configured to use the augenrules program to read audit rules during
daemon startup (the default), add a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/usr/bin/newgrp -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add a line of the following
form to /etc/audit/audit.rules :
-a always,exit -F path=/usr/bin/newgrp -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged Rationale:Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks,
which attempt to subvert their normal role of providing some necessary but
limited capability. As such, motivation exists to monitor these programs for
unusual activity. Identifiers:
CCE-85585-8 References:
1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000169, CCI-000135, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, CIP-004-3 R2.2.2, CIP-004-3 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SLES-15-030090, SV-234908r622137_rule, SRG-OS-000471-VMM-001910 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/newgrp -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85585-8
- DISA-STIG-SLES-15-030090
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_privileged_commands_newgrp
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /usr/bin/newgrp
block:
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/newgrp -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/newgrp -F perm=x
-F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/newgrp -F
perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/newgrp -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|")
}}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/newgrp -F perm=x -F auid>=1000
-F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/newgrp -F
perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85585-8
- DISA-STIG-SLES-15-030090
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_privileged_commands_newgrp
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure auditd Collects Information on the Use of Privileged Commands - pam_timestamp_check
[ref]ruleAt a minimum, the audit system should collect the execution of
privileged commands for all users and root. If the auditd daemon is
configured to use the augenrules program to read audit rules during
daemon startup (the default), add a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/sbin/pam_timestamp_check
-F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add a line of the following
form to /etc/audit/audit.rules :
-a always,exit -F path=/sbin/pam_timestamp_check
-F perm=x -F auid>=1000 -F auid!=unset -F key=privileged Rationale:Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks,
which attempt to subvert their normal role of providing some necessary but
limited capability. As such, motivation exists to monitor these programs for
unusual activity. Identifiers:
CCE-85601-3 References:
1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SLES-15-030510, SV-234950r622137_rule, SRG-OS-000471-VMM-001910 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/sbin/pam_timestamp_check -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85601-3
- DISA-STIG-SLES-15-030510
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_privileged_commands_pam_timestamp_check
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /sbin/pam_timestamp_check
block:
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/sbin/pam_timestamp_check -F perm=x -F auid>=1000 -F auid!=unset
(-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/sbin/pam_timestamp_check
-F perm=x -F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/sbin/pam_timestamp_check
-F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/sbin/pam_timestamp_check -F perm=x -F auid>=1000 -F auid!=unset
(-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|")
}}))\b)((?:( -S |,)\w+)+)( -F path=/sbin/pam_timestamp_check -F perm=x -F
auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/sbin/pam_timestamp_check
-F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85601-3
- DISA-STIG-SLES-15-030510
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_privileged_commands_pam_timestamp_check
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure auditd Collects Information on the Use of Privileged Commands - passmass
[ref]ruleAt a minimum, the audit system should collect the execution of
privileged commands for all users and root. If the auditd daemon is
configured to use the augenrules program to read audit rules during
daemon startup (the default), add a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/usr/bin/passmass -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add a line of the following
form to /etc/audit/audit.rules :
-a always,exit -F path=/usr/bin/passmass -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged Rationale:Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks,
which attempt to subvert their normal role of providing some necessary but
limited capability. As such, motivation exists to monitor these programs for
unusual activity. Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/passmass -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85599-9
- DISA-STIG-SLES-15-030490
- audit_rules_privileged_commands_passmass
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /usr/bin/passmass
block:
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/passmass -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/passmass -F perm=x
-F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/passmass -F
perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/passmass -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|")
}}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/passmass -F perm=x -F auid>=1000
-F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/passmass -F
perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85599-9
- DISA-STIG-SLES-15-030490
- audit_rules_privileged_commands_passmass
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure auditd Collects Information on the Use of Privileged Commands - passwd
[ref]ruleAt a minimum, the audit system should collect the execution of
privileged commands for all users and root. If the auditd daemon is
configured to use the augenrules program to read audit rules during
daemon startup (the default), add a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/usr/bin/passwd -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add a line of the following
form to /etc/audit/audit.rules :
-a always,exit -F path=/usr/bin/passwd -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged Rationale:Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks,
which attempt to subvert their normal role of providing some necessary but
limited capability. As such, motivation exists to monitor these programs for
unusual activity. Identifiers:
CCE-85583-3 References:
1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, CIP-004-3 R2.2.2, CIP-004-3 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SLES-15-030070, SV-234906r622137_rule, SRG-OS-000471-VMM-001910 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/passwd -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85583-3
- DISA-STIG-SLES-15-030070
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_privileged_commands_passwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /usr/bin/passwd
block:
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/passwd -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/passwd -F perm=x
-F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/passwd -F
perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/passwd -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|")
}}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/passwd -F perm=x -F auid>=1000
-F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/passwd -F
perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85583-3
- DISA-STIG-SLES-15-030070
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_privileged_commands_passwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure auditd Collects Information on the Use of Privileged Commands - rmmod
[ref]ruleAt a minimum, the audit system should collect the execution of
privileged commands for all users and root. If the auditd daemon is
configured to use the augenrules program to read audit rules during
daemon startup (the default), add a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d :
-w /sbin/rmmod -p x -k modules Rationale:Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks,
which attempt to subvert their normal role of providing some necessary but
limited capability. As such, motivation exists to monitor these programs for
unusual activity. Identifiers:
CCE-85732-6 References:
4.1.16, CCI-000130, CCI-000169, CCI-000172, CCI-002884, AU-12(c), AU-12.1(iv), AU-3, AU-3.1, AU-12(a), AU-12.1(ii), MA-4(1)(a), SRG-OS-000037-GPOS-00015, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SLES-15-030390, SV-234938r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/sbin/rmmod" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/sbin/rmmod $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "x" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/sbin/rmmod$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /sbin/rmmod -p x -k modules" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/modules.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/sbin/rmmod" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/modules.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/modules.rules"
# If the modules.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/sbin/rmmod" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/sbin/rmmod $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "x" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/sbin/rmmod$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /sbin/rmmod -p x -k modules" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85732-6
- DISA-STIG-SLES-15-030390
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_rmmod
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /sbin/rmmod already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/sbin/rmmod\s+-p\s+x(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85732-6
- DISA-STIG-SLES-15-030390
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_rmmod
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key modules
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)modules$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85732-6
- DISA-STIG-SLES-15-030390
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_rmmod
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use /etc/audit/rules.d/modules.rules as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/modules.rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85732-6
- DISA-STIG-SLES-15-030390
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_rmmod
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85732-6
- DISA-STIG-SLES-15-030390
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_rmmod
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /sbin/rmmod in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /sbin/rmmod -p x -k modules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85732-6
- DISA-STIG-SLES-15-030390
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_rmmod
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check if watch rule for /sbin/rmmod already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/sbin/rmmod\s+-p\s+x(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85732-6
- DISA-STIG-SLES-15-030390
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_rmmod
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Add watch rule for /sbin/rmmod in /etc/audit/audit.rules
lineinfile:
line: -w /sbin/rmmod -p x -k modules
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-85732-6
- DISA-STIG-SLES-15-030390
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_rmmod
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Record Any Attempts to Run ssh-agent
[ref]ruleAt a minimum, the audit system should collect any execution attempt
of the ssh-agent command for all users and root. If the auditd
daemon is configured to use the augenrules program to read audit rules
during daemon startup (the default), add the following lines to a file with suffix
.rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/usr/bin/ssh-agent -F perm=x -F auid>=1000 -F auid!=unset -k privileged-ssh-agent
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file:
-a always,exit -F path=/usr/bin/ssh-agent -F perm=x -F auid>=1000 -F auid!=unset -k privileged-ssh-agent Rationale:Without generating audit records that are specific to the security and
mission needs of the organization, it would be difficult to establish,
correlate, and investigate the events relating to an incident or identify
those responsible for one.
Audit records can be generated from various components within the
information system (e.g., module or policy filter). Identifiers:
CCE-85590-8 References:
CCI-000130, CCI-000169, CCI-000172, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SLES-15-030370, SV-234936r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/ssh-agent -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85590-8
- DISA-STIG-SLES-15-030370
- audit_rules_privileged_commands_ssh_agent
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /usr/bin/ssh-agent
block:
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/ssh-agent -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/ssh-agent -F perm=x
-F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/ssh-agent
-F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/ssh-agent -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|")
}}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/ssh-agent -F perm=x -F auid>=1000
-F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/ssh-agent
-F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85590-8
- DISA-STIG-SLES-15-030370
- audit_rules_privileged_commands_ssh_agent
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure auditd Collects Information on the Use of Privileged Commands - ssh-keysign
[ref]ruleAt a minimum, the audit system should collect the execution of
privileged commands for all users and root. If the auditd daemon is
configured to use the augenrules program to read audit rules during
daemon startup (the default), add a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/usr/lib/ssh/ssh-keysign -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add a line of the following
form to /etc/audit/audit.rules :
-a always,exit -F path=/usr/lib/ssh/ssh-keysign -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged Rationale:Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks,
which attempt to subvert their normal role of providing some necessary but
limited capability. As such, motivation exists to monitor these programs for
unusual activity. Identifiers:
CCE-85582-5 References:
1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SLES-15-030060, SV-234905r622137_rule, SRG-OS-000471-VMM-001910 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/lib/ssh/ssh-keysign -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85582-5
- DISA-STIG-SLES-15-030060
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_privileged_commands_ssh_keysign
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /usr/lib/ssh/ssh-keysign
block:
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/lib/ssh/ssh-keysign -F perm=x -F auid>=1000 -F auid!=unset
(-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/lib/ssh/ssh-keysign
-F perm=x -F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/lib/ssh/ssh-keysign
-F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/lib/ssh/ssh-keysign -F perm=x -F auid>=1000 -F auid!=unset
(-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|")
}}))\b)((?:( -S |,)\w+)+)( -F path=/usr/lib/ssh/ssh-keysign -F perm=x -F
auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/lib/ssh/ssh-keysign
-F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85582-5
- DISA-STIG-SLES-15-030060
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_privileged_commands_ssh_keysign
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure auditd Collects Information on the Use of Privileged Commands - su
[ref]ruleAt a minimum, the audit system should collect the execution of
privileged commands for all users and root. If the auditd daemon is
configured to use the augenrules program to read audit rules during
daemon startup (the default), add a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/usr/bin/su -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add a line of the following
form to /etc/audit/audit.rules :
-a always,exit -F path=/usr/bin/su -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged Rationale:Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks,
which attempt to subvert their normal role of providing some necessary but
limited capability. As such, motivation exists to monitor these programs for
unusual activity. Identifiers:
CCE-85602-1 References:
1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000064-GPOS-0003, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SLES-15-030550, SV-234954r622137_rule, SRG-OS-000471-VMM-001910 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/su -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85602-1
- DISA-STIG-SLES-15-030550
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_privileged_commands_su
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /usr/bin/su
block:
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/su -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/su -F perm=x -F
auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/su -F perm=x
-F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/su -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|")
}}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/su -F perm=x -F auid>=1000 -F
auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/su -F perm=x
-F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85602-1
- DISA-STIG-SLES-15-030550
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_privileged_commands_su
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure auditd Collects Information on the Use of Privileged Commands - sudo
[ref]ruleAt a minimum, the audit system should collect the execution of
privileged commands for all users and root. If the auditd daemon is
configured to use the augenrules program to read audit rules during
daemon startup (the default), add a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/usr/bin/sudo -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add a line of the following
form to /etc/audit/audit.rules :
-a always,exit -F path=/usr/bin/sudo -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged Rationale:Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks,
which attempt to subvert their normal role of providing some necessary but
limited capability. As such, motivation exists to monitor these programs for
unusual activity. Identifiers:
CCE-85603-9 References:
BP28(R19), 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SLES-15-030560, SV-234955r622137_rule, SRG-OS-000471-VMM-001910 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/sudo -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85603-9
- DISA-STIG-SLES-15-030560
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_privileged_commands_sudo
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /usr/bin/sudo
block:
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/sudo -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/sudo -F perm=x -F
auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/sudo -F perm=x
-F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/sudo -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|")
}}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/sudo -F perm=x -F auid>=1000
-F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/sudo -F perm=x
-F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85603-9
- DISA-STIG-SLES-15-030560
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- audit_rules_privileged_commands_sudo
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure auditd Collects Information on the Use of Privileged Commands - sudoedit
[ref]ruleAt a minimum, the audit system should collect the execution of
privileged commands for all users and root. If the auditd daemon is
configured to use the augenrules program to read audit rules during
daemon startup (the default), add a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/usr/bin/sudoedit -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add a line of the following
form to /etc/audit/audit.rules :
-a always,exit -F path=/usr/bin/sudoedit -F auid>=1000 -F auid!=unset -F key=privileged Rationale:Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks,
which attempt to subvert their normal role of providing some necessary but
limited capability. As such, motivation exists to monitor these programs for
unusual activity. Identifiers:
CCE-85717-7 References:
1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-3, AU-3.1, AU-12(a), AU-12.1(ii), AU-12.1(iv), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SLES-15-030330, SV-234932r622137_rule, SRG-OS-000471-VMM-001910 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/sudoedit -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85717-7
- DISA-STIG-SLES-15-030330
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- audit_rules_privileged_commands_sudoedit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /usr/bin/sudoedit
block:
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/sudoedit -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/sudoedit -F perm=x
-F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/sudoedit -F
perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/bin/sudoedit -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|")
}}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/sudoedit -F perm=x -F auid>=1000
-F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/sudoedit -F
perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85717-7
- DISA-STIG-SLES-15-030330
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- audit_rules_privileged_commands_sudoedit
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure auditd Collects Information on the Use of Privileged Commands - unix2_chkpwd
[ref]ruleAt a minimum, the audit system should collect the execution of
privileged commands for all users and root. If the auditd daemon is
configured to use the augenrules program to read audit rules during
daemon startup (the default), add a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/sbin/unix2_chkpwd -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add a line of the following
form to /etc/audit/audit.rules :
-a always,exit -F path=/sbin/unix2_chkpwd -F auid>=1000 -F auid!=unset -F key=privileged Rationale:Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks,
which attempt to subvert their normal role of providing some necessary but
limited capability. As such, motivation exists to monitor these programs for
unusual activity. Identifiers:
CCE-85762-3 References:
1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AC-2(4), AU-2(d), AU-3, AU-3.1, AU-12(a), AU-12(c), AU-12.1(ii), AU-12.1(iv), AC-6(9), CM-6(a), MA-4(1)(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000042-GPOS-00020, SRG-OS-000392-GPOS-00172, SRG-OS-000471-GPOS-00215, SRG-OS-000037-GPOS-00015, SLES-15-030110, SV-234910r622137_rule, SRG-OS-000471-VMM-001910 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/sbin/unix2_chkpwd -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85762-3
- DISA-STIG-SLES-15-030110
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-2(d)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-CM-6(a)
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_unix2_chkpwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /sbin/unix2_chkpwd
block:
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/sbin/unix2_chkpwd -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/sbin/unix2_chkpwd -F perm=x
-F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/sbin/unix2_chkpwd
-F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/sbin/unix2_chkpwd -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|")
}}))\b)((?:( -S |,)\w+)+)( -F path=/sbin/unix2_chkpwd -F perm=x -F auid>=1000
-F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/sbin/unix2_chkpwd
-F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85762-3
- DISA-STIG-SLES-15-030110
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-2(d)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-CM-6(a)
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_unix2_chkpwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure auditd Collects Information on the Use of Privileged Commands - unix_chkpwd
[ref]ruleAt a minimum, the audit system should collect the execution of
privileged commands for all users and root. If the auditd daemon is
configured to use the augenrules program to read audit rules during
daemon startup (the default), add a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/usr/sbin/unix_chkpwd -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add a line of the following
form to /etc/audit/audit.rules :
-a always,exit -F path=/usr/sbin/unix_chkpwd -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged Rationale:Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks,
which attempt to subvert their normal role of providing some necessary but
limited capability. As such, motivation exists to monitor these programs for
unusual activity. Identifiers:
CCE-85727-6 References:
1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, CIP-004-3 R2.2.2, CIP-004-3 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, CIP-007-3 R6.5, AC-2(4), AU-2(d), AU-3, AU-3.1, AU-12(a), AU-12(c), AU-12.1(ii), AU-12.1(iv), AC-6(9), CM-6(a), MA-4(1)(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SLES-15-030110, SV-234910r622137_rule, SRG-OS-000471-VMM-001910 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/sbin/unix_chkpwd -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85727-6
- DISA-STIG-SLES-15-030110
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-2(d)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-CM-6(a)
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_unix_chkpwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /sbin/unix_chkpwd
block:
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/sbin/unix_chkpwd -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/sbin/unix_chkpwd -F perm=x
-F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/sbin/unix_chkpwd -F
perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/sbin/unix_chkpwd -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|")
}}))\b)((?:( -S |,)\w+)+)( -F path=/sbin/unix_chkpwd -F perm=x -F auid>=1000
-F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/sbin/unix_chkpwd -F
perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85727-6
- DISA-STIG-SLES-15-030110
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-2(d)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-CM-6(a)
- NIST-800-53-MA-4(1)(a)
- audit_rules_privileged_commands_unix_chkpwd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure auditd Collects Information on the Use of Privileged Commands - usermod
[ref]ruleAt a minimum, the audit system should collect the execution of
privileged commands for all users and root. If the auditd daemon is
configured to use the augenrules program to read audit rules during
daemon startup (the default), add a line of the following form to a file with
suffix .rules in the directory /etc/audit/rules.d :
-a always,exit -F path=/usr/sbin/usermod -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add a line of the following
form to /etc/audit/audit.rules :
-a always,exit -F path=/usr/sbin/usermod -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged Rationale:Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have compromised system accounts,
is a serious and ongoing concern and can have significant adverse impacts on organizations.
Auditing the use of privileged functions is one way to detect such misuse and identify
the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks,
which attempt to subvert their normal role of providing some necessary but
limited capability. As such, motivation exists to monitor these programs for
unusual activity. Identifiers:
CCE-85600-5 References:
CCI-000130, CCI-000169, CCI-000172, CCI-002884, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SLES-15-030500, SV-234949r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/sbin/usermod -F perm=x"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85600-5
- DISA-STIG-SLES-15-030500
- audit_rules_privileged_commands_usermod
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Perform remediation of Audit rules for /usr/sbin/usermod
block:
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/sbin/usermod -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/usermod -F perm=x
-F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/usermod -F
perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls: []
syscall_grouping: []
- name: Check existence of in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)*
-F path=/usr/sbin/usermod -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|")
}}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/usermod -F perm=x -F auid>=1000
-F auid!=unset (?:-k |-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/usermod -F
perm=x -F auid>=1000 -F auid!=unset -F key=privileged
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85600-5
- DISA-STIG-SLES-15-030500
- audit_rules_privileged_commands_usermod
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Remove Default Configuration to Disable Syscall Auditing
[ref]ruleBy default, SUSE Linux Enterprise 15 ships an audit rule to disable syscall
auditing for performance reasons.
To make sure that syscall auditing works, this line must be removed from
/etc/audit/rules.d/audit.rules and /etc/audit/audit.rules :
-a task,never Rationale:Audit rules for syscalls do not take effect unless this line is removed. Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
if [ -f "/usr/lib/systemd/system/auditd.service" ] ; then
EXECSTARTPOST_SCRIPT=$(grep '^ExecStartPost=' /usr/lib/systemd/system/auditd.service | sed 's/ExecStartPost=//')
if [[ "$EXECSTARTPOST_SCRIPT" == *"augenrules"* ]] ; then
for f in /etc/audit/rules.d/*.rules ; do
sed -E -i --follow-symlinks 's/^(\s*-a\s+task,never)/#\1/' "$f"
done
else
# auditctl is used
sed -E -i --follow-symlinks 's/^(\s*-a\s+task,never)/#\1/' /etc/audit/audit.rules
fi
systemctl is-active --quiet auditd.service
if [ $? -ne 0 ] ; then
systemctl restart auditd.service
fi
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85706-0
- DISA-STIG-SLES-15-030820
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- audit_rules_enable_syscall_auditing
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Service facts
service_facts: null
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85706-0
- DISA-STIG-SLES-15-030820
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- audit_rules_enable_syscall_auditing
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check the rules script being used
command: grep '^ExecStartPost' /usr/lib/systemd/system/auditd.service
register: check_rules_scripts_result
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85706-0
- DISA-STIG-SLES-15-030820
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- audit_rules_enable_syscall_auditing
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Find audit rules in /etc/audit/rules.d
find:
paths: /etc/audit/rules.d
file_type: file
follow: true
register: find_audit_rules_result
when:
- '"audit" in ansible_facts.packages'
- '"auditd.service" in ansible_facts.services'
- '"augenrules" in check_rules_scripts_result.stdout'
tags:
- CCE-85706-0
- DISA-STIG-SLES-15-030820
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- audit_rules_enable_syscall_auditing
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Enable syscall auditing (augenrules)
lineinfile:
path: '{{ item.path }}'
regex: ^(?i)(\s*-a\s+task,never)\s*$
line: '#-a task,never'
with_items: '{{ find_audit_rules_result.files }}'
when:
- '"audit" in ansible_facts.packages'
- '"auditd.service" in ansible_facts.services'
- '"augenrules" in check_rules_scripts_result.stdout'
register: augenrules_syscall_auditing_rule_update_result
tags:
- CCE-85706-0
- DISA-STIG-SLES-15-030820
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- audit_rules_enable_syscall_auditing
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Enable syscall auditing (auditctl)
lineinfile:
path: /etc/audit/audit.rules
regex: ^(?i)(\s*-a\s+task,never)\s*$
line: '#-a task,never'
when:
- '"audit" in ansible_facts.packages'
- '"auditd.service" in ansible_facts.services'
- '"auditctl" in check_rules_scripts_result.stdout'
register: auditctl_syscall_auditing_rule_update_result
tags:
- CCE-85706-0
- DISA-STIG-SLES-15-030820
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- audit_rules_enable_syscall_auditing
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Restart auditd.service
systemd:
name: auditd.service
state: restarted
when:
- '"audit" in ansible_facts.packages'
- ansible_facts.services["auditd.service"].state == "running"
- (augenrules_syscall_auditing_rule_update_result.changed or auditctl_syscall_auditing_rule_update_result.changed)
tags:
- CCE-85706-0
- DISA-STIG-SLES-15-030820
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- audit_rules_enable_syscall_auditing
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure auditd Collects Information on Exporting to Media (successful)
[ref]ruleAt a minimum, the audit system should collect media exportation
events for all users and root. If the auditd daemon is configured to
use the augenrules program to read audit rules during daemon startup
(the default), add the following line to a file with suffix .rules in
the directory /etc/audit/rules.d , setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S mount -F auid>=1000 -F auid!=unset -F key=export
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file, setting ARCH to either b32 or b64 as
appropriate for your system:
-a always,exit -F arch=ARCH -S mount -F auid>=1000 -F auid!=unset -F key=export Rationale:The unauthorized exportation of data to external media could result in an information leak
where classified information, Privacy Act information, and intellectual property could be lost. An audit
trail should be created each time a filesystem is mounted to help identify and guard against information
loss. Identifiers:
CCE-85718-5 References:
4.1.12, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000135, CCI-000169, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.2.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SLES-15-030350, SV-234934r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS=""
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="mount"
KEY="perm_mod"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85718-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030350
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_media_export
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit mount tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85718-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030350
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_media_export
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for mount for x86 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- mount
syscall_grouping: []
- name: Check existence of mount in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- mount
syscall_grouping: []
- name: Check existence of mount in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85718-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030350
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_media_export
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Perform remediation of Audit rules for mount for x86_64 platform
block:
- name: Declare list of syscalls
set_fact:
syscalls:
- mount
syscall_grouping: []
- name: Check existence of mount in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: '*.rules'
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Reset syscalls found per file
set_fact:
syscalls_per_file: {}
found_paths_dict: {}
- name: Declare syscalls found per file
set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
:[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
loop: '{{ find_command.results | selectattr(''matched'') | list }}'
- name: Declare files where syscalls were found
set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
| map(attribute='path') | list }}"
- name: Count occurrences of syscalls in paths
set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
0) }) }}"
loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
| list }}'
- name: Get path with most syscalls
set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
| last).key }}"
when: found_paths | length >= 1
- name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
when: found_paths | length == 0
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
- name: Declare list of syscalls
set_fact:
syscalls:
- mount
syscall_grouping: []
- name: Check existence of mount in /etc/audit/audit.rules
find:
paths: /etc/audit
contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+((
-S |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
patterns: audit.rules
register: find_command
loop: '{{ (syscall_grouping + syscalls) | unique }}'
- name: Set path to /etc/audit/audit.rules
set_fact: audit_file="/etc/audit/audit.rules"
- name: Declare found syscalls
set_fact: syscalls_found="{{ find_command.results | selectattr('matched') |
map(attribute='item') | list }}"
- name: Declare missing syscalls
set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"
- name: Replace the audit rule in {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found
| join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
|-F key=)\w+)
line: \1\2\3{{ missing_syscalls | join("\3") }}\4
backrefs: true
state: present
when: syscalls_found | length > 0 and missing_syscalls | length > 0
- name: Add the audit rule to {{ audit_file }}
lineinfile:
path: '{{ audit_file }}'
line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
-F auid!=unset -F key=perm_mod
create: true
mode: o-rwx
state: present
when: syscalls_found | length == 0
when:
- '"audit" in ansible_facts.packages'
- audit_arch == "b64"
tags:
- CCE-85718-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030350
- NIST-800-171-3.1.7
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.7
- audit_rules_media_export
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Attempts to Alter Process and Session Initiation Information btmp
[ref]ruleThe audit system already collects process information for all
users and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d in order to watch for attempted manual
edits of files involved in storing such process information:
-w /var/log/btmp -p wa -k session
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file in order to watch for attempted manual
edits of files involved in storing such process information:
-w /var/log/btmp -p wa -k session Rationale:Manual editing of these files may indicate nefarious activity, such
as an attacker attempting to remove evidence of an intrusion. Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/var/log/btmp" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/btmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/btmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/btmp -p wa -k session" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/session.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/log/btmp" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/session.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/session.rules"
# If the session.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/var/log/btmp" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/btmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/btmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/btmp -p wa -k session" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85758-1
- DISA-STIG-SLES-15-030780
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_session_events_btmp
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /var/log/btmp already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/var/log/btmp\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85758-1
- DISA-STIG-SLES-15-030780
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_session_events_btmp
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key session
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)session$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85758-1
- DISA-STIG-SLES-15-030780
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_session_events_btmp
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use /etc/audit/rules.d/session.rules as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/session.rules
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85758-1
- DISA-STIG-SLES-15-030780
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_session_events_btmp
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85758-1
- DISA-STIG-SLES-15-030780
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_session_events_btmp
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /var/log/btmp in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /var/log/btmp -p wa -k session
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85758-1
- DISA-STIG-SLES-15-030780
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_session_events_btmp
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /var/log/btmp already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/var/log/btmp\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85758-1
- DISA-STIG-SLES-15-030780
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_session_events_btmp
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /var/log/btmp in /etc/audit/audit.rules
lineinfile:
line: -w /var/log/btmp -p wa -k session
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-85758-1
- DISA-STIG-SLES-15-030780
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_session_events_btmp
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Attempts to Alter Process and Session Initiation Information utmp
[ref]ruleThe audit system already collects process information for all
users and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d in order to watch for attempted manual
edits of files involved in storing such process information:
-w /run/utmp -p wa -k session
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file in order to watch for attempted manual
edits of files involved in storing such process information:
-w /run/utmp -p wa -k session Rationale:Manual editing of these files may indicate nefarious activity, such
as an attacker attempting to remove evidence of an intrusion. Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/run/utmp" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/run/utmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/run/utmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /run/utmp -p wa -k session" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/session.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/run/utmp" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/session.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/session.rules"
# If the session.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/run/utmp" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/run/utmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/run/utmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /run/utmp -p wa -k session" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85714-4
- DISA-STIG-SLES-15-030760
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_session_events_utmp
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /run/utmp already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/run/utmp\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85714-4
- DISA-STIG-SLES-15-030760
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_session_events_utmp
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key session
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)session$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85714-4
- DISA-STIG-SLES-15-030760
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_session_events_utmp
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use /etc/audit/rules.d/session.rules as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/session.rules
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85714-4
- DISA-STIG-SLES-15-030760
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_session_events_utmp
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85714-4
- DISA-STIG-SLES-15-030760
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_session_events_utmp
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /run/utmp in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /run/utmp -p wa -k session
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85714-4
- DISA-STIG-SLES-15-030760
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_session_events_utmp
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /run/utmp already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/run/utmp\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85714-4
- DISA-STIG-SLES-15-030760
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_session_events_utmp
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /run/utmp in /etc/audit/audit.rules
lineinfile:
line: -w /run/utmp -p wa -k session
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-85714-4
- DISA-STIG-SLES-15-030760
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_session_events_utmp
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Attempts to Alter Process and Session Initiation Information wtmp
[ref]ruleThe audit system already collects process information for all
users and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d in order to watch for attempted manual
edits of files involved in storing such process information:
-w /var/log/wtmp -p wa -k session
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file in order to watch for attempted manual
edits of files involved in storing such process information:
-w /var/log/wtmp -p wa -k session Rationale:Manual editing of these files may indicate nefarious activity, such
as an attacker attempting to remove evidence of an intrusion. Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/var/log/wtmp" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/wtmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/wtmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/wtmp -p wa -k session" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/session.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/log/wtmp" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/session.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/session.rules"
# If the session.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/var/log/wtmp" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/wtmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/var/log/wtmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /var/log/wtmp -p wa -k session" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85757-3
- DISA-STIG-SLES-15-030770
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_session_events_wtmp
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /var/log/wtmp already exists in /etc/audit/rules.d/
find:
paths: /etc/audit/rules.d
contains: ^\s*-w\s+/var/log/wtmp\s+-p\s+wa(\s|$)+
patterns: '*.rules'
register: find_existing_watch_rules_d
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85757-3
- DISA-STIG-SLES-15-030770
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_session_events_wtmp
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other rules with specified key session
find:
paths: /etc/audit/rules.d
contains: ^.*(?:-F key=|-k\s+)session$
patterns: '*.rules'
register: find_watch_key
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85757-3
- DISA-STIG-SLES-15-030770
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_session_events_wtmp
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use /etc/audit/rules.d/session.rules as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/session.rules
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85757-3
- DISA-STIG-SLES-15-030770
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_session_events_wtmp
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
is defined and find_existing_watch_rules_d.matched == 0
tags:
- CCE-85757-3
- DISA-STIG-SLES-15-030770
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_session_events_wtmp
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /var/log/wtmp in /etc/audit/rules.d/
lineinfile:
path: '{{ all_files[0] }}'
line: -w /var/log/wtmp -p wa -k session
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
== 0
tags:
- CCE-85757-3
- DISA-STIG-SLES-15-030770
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_session_events_wtmp
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Check if watch rule for /var/log/wtmp already exists in /etc/audit/audit.rules
find:
paths: /etc/audit/
contains: ^\s*-w\s+/var/log/wtmp\s+-p\s+wa(\s|$)+
patterns: audit.rules
register: find_existing_watch_audit_rules
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85757-3
- DISA-STIG-SLES-15-030770
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_session_events_wtmp
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Add watch rule for /var/log/wtmp in /etc/audit/audit.rules
lineinfile:
line: -w /var/log/wtmp -p wa -k session
state: present
dest: /etc/audit/audit.rules
create: true
mode: '0640'
when:
- '"audit" in ansible_facts.packages'
- find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
== 0
tags:
- CCE-85757-3
- DISA-STIG-SLES-15-030770
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-12.1(iv)
- audit_rules_session_events_wtmp
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Events When Privileged Executables Are Run
[ref]ruleVerify the system generates an audit record when privileged functions are executed.
# grep -iw execve /etc/audit/audit.rules
-a always,exit -F arch=b32 -S execve -C uid!=euid -F euid=0 -k setuid
-a always,exit -F arch=b64 -S execve -C uid!=euid -F euid=0 -k setuid
-a always,exit -F arch=b32 -S execve -C gid!=egid -F egid=0 -k setgid
-a always,exit -F arch=b64 -S execve -C gid!=egid -F egid=0 -k setgid
If both the "b32" and "b64" audit rules for "SUID" files are not defined, this is a finding.
If both the "b32" and "b64" audit rules for "SGID" files are not defined, this is a finding.Warning:
Note that these rules can be configured in a
number of ways while still achieving the desired effect. Rationale:Misuse of privileged functions, either intentionally or unintentionally by
authorized users, or by unauthorized external entities that have
compromised information system accounts, is a serious and ongoing concern
and can have significant adverse impacts on organizations. Auditing the use
of privileged functions is one way to detect such misuse and identify the
risk from insider threats and the advanced persistent threat. Identifiers:
CCE-85611-2 References:
CCI-001814, CCI-001882, CCI-001889, CCI-001880, CCI-001881, CCI-001878, CCI-001879, CCI-001875, CCI-001877, CCI-001914, CCI-002234, CM-5(1), AU-7(a), AU-7(b), AU-8(b), AU-12(3), AC-6(9), SRG-OS-000326-GPOS-00126, SRG-OS-000327-GPOS-00127, SRG-OS-000337-GPOS-00129, SRG-OS-000348-GPOS-00136, SRG-OS-000349-GPOS-00137, SRG-OS-000350-GPOS-00138, SRG-OS-000351-GPOS-00139, SRG-OS-000352-GPOS-00140, SRG-OS-000353-GPOS-00141, SRG-OS-000354-GPOS-00142, SRG-OS-000358-GPOS-00145, SRG-OS-000359-GPOS-00146, SRG-OS-000365-GPOS-00152, SLES-15-030640, SV-234963r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS="-C uid!=euid -F euid=0"
AUID_FILTERS=""
SYSCALL="execve"
KEY="setuid"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
for ARCH in "${RULE_ARCHS[@]}"
do
ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
OTHER_FILTERS="-C gid!=egid -F egid=0"
AUID_FILTERS=""
SYSCALL="execve"
KEY="setgid"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
file_to_inspect="/etc/audit/rules.d/$KEY.rules"
files_to_inspect=("$file_to_inspect")
if [ ! -e "$file_to_inspect" ]
then
touch "$file_to_inspect"
chmod 0640 "$file_to_inspect"
fi
fi
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()
# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )
# Indicator that we want to append $full_rule into $audit_file or edit a rule in it
append_expected_rule=0
# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1
for audit_file in "${files_to_inspect[@]}"
do
# Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
# i.e, collect rules that match:
# * the action, list and arch, (2-nd argument)
# * the other filters, (3-rd argument)
# * the auid filters, (4-rd argument)
readarray -t similar_rules < <(sed -e "/$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")
candidate_rules=()
# Filter out rules that have more fields then required. This will remove rules more specific than the required scope
for s_rule in "${similar_rules[@]}"
do
# Strip all the options and fields we know of,
# than check if there was any field left over
extra_fields=$(sed -E -e "s/$ACTION_ARCH_FILTERS//" -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
grep -q -- "-F" <<< "$extra_fields"
if [ $? -ne 0 ]
then
candidate_rules+=("$s_rule")
fi
done
if [[ ${#syscall_a[@]} -ge 1 ]]
then
# Check if the syscall we want is present in any of the similar existing rules
for rule in "${candidate_rules[@]}"
do
rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
all_syscalls_found=0
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "$rule_syscalls"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
all_syscalls_found=1
fi
done
if [[ $all_syscalls_found -eq 0 ]]
then
# We found a rule with all the syscall(s) we want; skip rest of macro
skip=0
break
fi
# Check if this rule can be grouped with our target syscall and keep track of it
for syscall_g in "${syscall_grouping[@]}"
do
if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
then
file_to_edit=${audit_file}
rule_to_edit=${rule}
rule_syscalls_to_edit=${rule_syscalls}
fi
done
done
else
# If there is any candidate rule, it is compliant; skip rest of macro
if [[ $candidate_rules ]]
then
skip=0
fi
fi
if [ "$skip" -eq 0 ]; then
break
fi
done
if [ "$skip" -ne 0 ]; then
# We checked all rules that matched the expected resemblance pattern (action, arch & auid)
# At this point we know if we need to either append the $full_rule or group
# the syscall together with an exsiting rule
# Append the full_rule if it cannot be grouped to any other rule
if [ -z ${rule_to_edit+x} ]
then
# Build full_rule while avoid adding double spaces when other_filters is empty
if [[ ${syscall_a} ]]
then
syscall_string=""
for syscall in "${syscall_a[@]}"
do
syscall_string+=" -S $syscall"
done
fi
other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS")
auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS")
full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY"
echo "$full_rule" >> "$default_file"
chmod o-rwx ${default_file}
else
# Check if the syscalls are declared as a comma separated list or
# as multiple -S parameters
if grep -q -- "," <<< "${rule_syscalls_to_edit}"
then
delimiter=","
else
delimiter=" -S "
fi
new_grouped_syscalls="${rule_syscalls_to_edit}"
for syscall in "${syscall_a[@]}"
do
grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}"
if [ $? -eq 1 ]
then
# A syscall was not found in the candidate rule
new_grouped_syscalls+="${delimiter}${syscall}"
fi
done
# Group the syscall in the rule
sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
fi
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85611-2
- DISA-STIG-SLES-15-030640
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(3)
- NIST-800-53-AU-7(a)
- NIST-800-53-AU-7(b)
- NIST-800-53-AU-8(b)
- NIST-800-53-CM-5(1)
- audit_rules_suid_privilege_function
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Service facts
service_facts: null
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85611-2
- DISA-STIG-SLES-15-030640
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(3)
- NIST-800-53-AU-7(a)
- NIST-800-53-AU-7(b)
- NIST-800-53-AU-8(b)
- NIST-800-53-CM-5(1)
- audit_rules_suid_privilege_function
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check the rules script being used
command: grep '^ExecStartPost' /usr/lib/systemd/system/auditd.service
register: check_rules_scripts_result
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85611-2
- DISA-STIG-SLES-15-030640
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(3)
- NIST-800-53-AU-7(a)
- NIST-800-53-AU-7(b)
- NIST-800-53-AU-8(b)
- NIST-800-53-CM-5(1)
- audit_rules_suid_privilege_function
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set suid_audit_rules fact
set_fact:
suid_audit_rules:
- -a always,exit -F arch=b32 -S execve -C gid!=egid -F egid=0 -k setgid
- -a always,exit -F arch=b64 -S execve -C gid!=egid -F egid=0 -k setgid
- -a always,exit -F arch=b32 -S execve -C uid!=euid -F euid=0 -k setuid
- -a always,exit -F arch=b64 -S execve -C uid!=euid -F euid=0 -k setuid
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85611-2
- DISA-STIG-SLES-15-030640
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(3)
- NIST-800-53-AU-7(a)
- NIST-800-53-AU-7(b)
- NIST-800-53-AU-8(b)
- NIST-800-53-CM-5(1)
- audit_rules_suid_privilege_function
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Update /etc/audit/rules.d/privileged.rules to audit privileged functions
lineinfile:
path: /etc/audit/rules.d/privileged.rules
line: '{{ item }}'
create: true
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"auditd.service" in ansible_facts.services'
- '"augenrules" in check_rules_scripts_result.stdout'
register: augenrules_audit_rules_privilege_function_update_result
with_items: '{{ suid_audit_rules }}'
tags:
- CCE-85611-2
- DISA-STIG-SLES-15-030640
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(3)
- NIST-800-53-AU-7(a)
- NIST-800-53-AU-7(b)
- NIST-800-53-AU-8(b)
- NIST-800-53-CM-5(1)
- audit_rules_suid_privilege_function
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Update Update /etc/audit/audit.rules to audit privileged functions
lineinfile:
path: /etc/audit/audit.rules
line: '{{ item }}'
create: true
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"auditd.service" in ansible_facts.services'
- '"auditctl" in check_rules_scripts_result.stdout'
register: auditctl_audit_rules_privilege_function_update_result
with_items: '{{ suid_audit_rules }}'
tags:
- CCE-85611-2
- DISA-STIG-SLES-15-030640
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(3)
- NIST-800-53-AU-7(a)
- NIST-800-53-AU-7(b)
- NIST-800-53-AU-8(b)
- NIST-800-53-CM-5(1)
- audit_rules_suid_privilege_function
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Restart auditd.service
systemd:
name: auditd.service
state: restarted
when:
- '"audit" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- (augenrules_audit_rules_privilege_function_update_result.changed or auditctl_audit_rules_privilege_function_update_result.changed)
- ansible_facts.services["auditd.service"].state == "running"
tags:
- CCE-85611-2
- DISA-STIG-SLES-15-030640
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(3)
- NIST-800-53-AU-7(a)
- NIST-800-53-AU-7(b)
- NIST-800-53-AU-8(b)
- NIST-800-53-CM-5(1)
- audit_rules_suid_privilege_function
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure auditd Collects System Administrator Actions
[ref]ruleAt a minimum, the audit system should collect administrator actions
for all users and root. If the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the default),
add the following line to a file with suffix .rules in the directory
/etc/audit/rules.d :
-w /etc/sudoers -p wa -k actions
-w /etc/sudoers.d/ -p wa -k actions
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following line to
/etc/audit/audit.rules file:
-w /etc/sudoers -p wa -k actions
-w /etc/sudoers.d/ -p wa -k actions Rationale:The actions taken by system administrators should be audited to keep a record
of what was executed on the system, as well as, for accountability purposes. Identifiers:
CCE-85679-9 References:
4.1.14, 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, AU-3, AU-3.1, AU-12(a), AU-12.1(ii), AU-12.1(iv), MA-4(1)(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.2, Req-10.2.5.b, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, CCI-002884, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SLES-15-030140, SV-234913r622137_rule, SRG-OS-000462-VMM-001840, SRG-OS-000471-VMM-001910 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/etc/sudoers" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sudoers $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/sudoers$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/sudoers -p wa -k actions" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/actions.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/sudoers" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/actions.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/actions.rules"
# If the actions.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/etc/sudoers" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sudoers $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/sudoers$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/sudoers -p wa -k actions" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/etc/sudoers.d/" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sudoers.d/ $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/sudoers.d/$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/sudoers.d/ -p wa -k actions" >> "$audit_rules_file"
fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules | Rule already defined | Audit rules file to inspect |
# -----------------------------------------------------------------------------------------
# auditctl | Doesn't matter | /etc/audit/audit.rules |
# -----------------------------------------------------------------------------------------
# augenrules | Yes | /etc/audit/rules.d/*.rules |
# augenrules | No | /etc/audit/rules.d/$key.rules |
# -----------------------------------------------------------------------------------------
files_to_inspect=()
# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/actions.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/sudoers.d/" /etc/audit/rules.d/*.rules)
# For each of the matched entries
for match in "${matches[@]}"
do
# Extract filepath from the match
rulesd_audit_file=$(echo $match | cut -f1 -d ':')
# Append that path into list of files for inspection
files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
# Append '/etc/audit/rules.d/actions.rules' into list of files for inspection
key_rule_file="/etc/audit/rules.d/actions.rules"
# If the actions.rules file doesn't exist yet, create it with correct permissions
if [ ! -e "$key_rule_file" ]
then
touch "$key_rule_file"
chmod 0640 "$key_rule_file"
fi
files_to_inspect+=("$key_rule_file")
fi
# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
# Check if audit watch file system object rule for given path already present
if grep -q -P -- "[\s]*-w[\s]+/etc/sudoers.d/" "$audit_rules_file"
then
# Rule is found => verify yet if existing rule definition contains
# all of the required access type bits
# Define BRE whitespace class shortcut
sp="[[:space:]]"
# Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sudoers.d/ $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
# Split required access bits string into characters array
# (to check bit's presence for one bit at a time)
for access_bit in $(echo "wa" | grep -o .)
do
# For each from the required access bits (e.g. 'w', 'a') check
# if they are already present in current access bits for rule.
# If not, append that bit at the end
if ! grep -q "$access_bit" <<< "$current_access_bits"
then
# Concatenate the existing mask with the missing bit
current_access_bits="$current_access_bits$access_bit"
fi
done
# Propagate the updated rule's access bits (original + the required
# ones) back into the /etc/audit/audit.rules file for that rule
sed -i "s#\($sp*-w$sp\+/etc/sudoers.d/$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
else
# Rule isn't present yet. Append it at the end of $audit_rules_file file
# with proper key
echo "-w /etc/sudoers.d/ -p wa -k actions" >> "$audit_rules_file"
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85679-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030140
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Search /etc/audit/rules.d for audit rule entries for sysadmin actions
find:
paths: /etc/audit/rules.d
recurse: false
contains: ^.*/etc/sudoers.*$
patterns: '*.rules'
register: find_audit_sysadmin_actions
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85679-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030140
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use /etc/audit/rules.d/actions.rules as the recipient for the rule
set_fact:
all_sysadmin_actions_files:
- /etc/audit/rules.d/actions.rules
when:
- '"audit" in ansible_facts.packages'
- find_audit_sysadmin_actions.matched is defined and find_audit_sysadmin_actions.matched
== 0
tags:
- CCE-85679-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030140
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_sysadmin_actions_files:
- '{{ find_audit_sysadmin_actions.files | map(attribute=''path'') | list | first
}}'
when:
- '"audit" in ansible_facts.packages'
- find_audit_sysadmin_actions.matched is defined and find_audit_sysadmin_actions.matched
> 0
tags:
- CCE-85679-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030140
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Inserts/replaces audit rule for /etc/sudoers rule in rules.d
lineinfile:
path: '{{ all_sysadmin_actions_files[0] }}'
line: -w /etc/sudoers -p wa -k actions
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85679-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030140
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Inserts/replaces audit rule for /etc/sudoers.d rule in rules.d
lineinfile:
path: '{{ all_sysadmin_actions_files[0] }}'
line: -w /etc/sudoers.d/ -p wa -k actions
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85679-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030140
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Inserts/replaces audit rule for /etc/sudoers in audit.rules
lineinfile:
path: /etc/audit/audit.rules
line: -w /etc/sudoers -p wa -k actions
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85679-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030140
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Inserts/replaces audit rule for /etc/sudoers.d in audit.rules
lineinfile:
path: /etc/audit/audit.rules
line: -w /etc/sudoers.d/ -p wa -k actions
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85679-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030140
- NIST-800-171-3.1.7
- NIST-800-53-AU-12(a)
- NIST-800-53-AU-12.1(ii)
- NIST-800-53-AU-12.1(iv)
- NIST-800-53-AU-3
- NIST-800-53-AU-3.1
- NIST-800-53-MA-4(1)(a)
- PCI-DSS-Req-10.2.2
- PCI-DSS-Req-10.2.5.b
- audit_rules_sysadmin_actions
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Record Events that Modify User/Group Information - /etc/group
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d , in order to capture events that modify
account changes:
-w /etc/group -p wa -k audit_rules_usergroup_modification
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file, in order to capture events that modify
account changes:
-w /etc/group -p wa -k audit_rules_usergroup_modification Rationale:In addition to auditing new user and group accounts, these watches
will alert the system administrator(s) to any modifications. Any unexpected
users, groups, or modifications should be investigated for legitimacy. Identifiers:
CCE-85578-3 References:
4.1.4, 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000169, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-3 R2.2.2, CIP-004-3 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, CCI-002884, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SLES-15-030010, SV-234900r622137_rule, SRG-OS-000004-VMM-000040, SRG-OS-000239-VMM-000810, SRG-OS-000240-VMM-000820, SRG-OS-000241-VMM-000830, SRG-OS-000274-VMM-000960, SRG-OS-000275-VMM-000970, SRG-OS-000276-VMM-000980, SRG-OS-000277-VMM-000990, SRG-OS-000303-VMM-001090, SRG-OS-000304-VMM-001100, SRG-OS-000476-VMM-001960 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85578-3
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030010
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_group
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit group tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85578-3
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030010
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_group
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other user/group modification audit rules
find:
paths: /etc/audit/rules.d
recurse: false
contains: -k audit_rules_usergroup_modification$
patterns: '*.rules'
register: find_group
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85578-3
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030010
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_group
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: If existing user/group modification ruleset not found, use /etc/audit/rules.d/privileged.rules
as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/privileged.rules
when:
- '"audit" in ansible_facts.packages'
- find_group.matched is defined and find_group.matched == 0
tags:
- CCE-85578-3
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030010
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_group
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_group.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_group.matched is defined and find_group.matched > 0
tags:
- CCE-85578-3
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030010
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_group
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the group rule in rules.d when on x86
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/group -p wa -k audit_rules_usergroup_modification
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85578-3
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030010
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_group
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the group rule in /etc/audit/audit.rules
lineinfile:
line: -w /etc/group -p wa -k audit_rules_usergroup_modification
state: present
dest: /etc/audit/audit.rules
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85578-3
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030010
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_group
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Events that Modify User/Group Information - /etc/gshadow
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d , in order to capture events that modify
account changes:
-w /etc/gshadow -p wa -k audit_rules_usergroup_modification
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file, in order to capture events that modify
account changes:
-w /etc/gshadow -p wa -k audit_rules_usergroup_modification Rationale:In addition to auditing new user and group accounts, these watches
will alert the system administrator(s) to any modifications. Any unexpected
users, groups, or modifications should be investigated for legitimacy. Identifiers:
CCE-85580-9 References:
4.1.4, 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000169, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-3 R2.2.2, CIP-004-3 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SLES-15-030040, SV-234903r622137_rule, SRG-OS-000004-VMM-000040, SRG-OS-000239-VMM-000810, SRG-OS-000240-VMM-000820, SRG-OS-000241-VMM-000830, SRG-OS-000274-VMM-000960, SRG-OS-000275-VMM-000970, SRG-OS-000276-VMM-000980, SRG-OS-000277-VMM-000990, SRG-OS-000303-VMM-001090, SRG-OS-000304-VMM-001100, SRG-OS-000476-VMM-001960 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85580-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030040
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_gshadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit gshadow tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85580-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030040
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_gshadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other user/group modification audit rules
find:
paths: /etc/audit/rules.d
recurse: false
contains: -k audit_rules_usergroup_modification$
patterns: '*.rules'
register: find_gshadow
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85580-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030040
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_gshadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: If existing user/group modification ruleset not found, use /etc/audit/rules.d/privileged.rules
as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/privileged.rules
when:
- '"audit" in ansible_facts.packages'
- find_gshadow.matched is defined and find_gshadow.matched == 0
tags:
- CCE-85580-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030040
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_gshadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_gshadow.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_gshadow.matched is defined and find_gshadow.matched > 0
tags:
- CCE-85580-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030040
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_gshadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the gshadow rule in rules.d when on x86
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/gshadow -p wa -k audit_rules_usergroup_modification
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85580-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030040
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_gshadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the gshadow rule in /etc/audit/audit.rules
lineinfile:
line: -w /etc/gshadow -p wa -k audit_rules_usergroup_modification
state: present
dest: /etc/audit/audit.rules
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85580-9
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030040
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_gshadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Events that Modify User/Group Information - /etc/security/opasswd
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d , in order to capture events that modify
account changes:
-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file, in order to capture events that modify
account changes:
-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification Rationale:In addition to auditing new user and group accounts, these watches
will alert the system administrator(s) to any modifications. Any unexpected
users, groups, or modifications should be investigated for legitimacy. Identifiers:
CCE-85728-4 References:
4.1.4, 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000169, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-3 R2.2.2, CIP-004-3 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4).1(i&ii), AU-12.1(iv), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, SRG-OS-000476-GPOS-00221, SRG-OS-000463-GPOS-00207, SLES-15-030030, SV-234902r622137_rule, SRG-OS-000004-VMM-000040, SRG-OS-000239-VMM-000810, SRG-OS-000240-VMM-000820, SRG-OS-000241-VMM-000830, SRG-OS-000274-VMM-000960, SRG-OS-000275-VMM-000970, SRG-OS-000276-VMM-000980, SRG-OS-000277-VMM-000990, SRG-OS-000303-VMM-001090, SRG-OS-000304-VMM-001100, SRG-OS-000476-VMM-001960 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85728-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030030
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4).1(i&ii)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_opasswd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit opasswd tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85728-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030030
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4).1(i&ii)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_opasswd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other user/group modification audit rules
find:
paths: /etc/audit/rules.d
recurse: false
contains: -k audit_rules_usergroup_modification$
patterns: '*.rules'
register: find_opasswd
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85728-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030030
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4).1(i&ii)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_opasswd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: If existing user/group modification ruleset not found, use /etc/audit/rules.d/privileged.rules
as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/privileged.rules
when:
- '"audit" in ansible_facts.packages'
- find_opasswd.matched is defined and find_opasswd.matched == 0
tags:
- CCE-85728-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030030
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4).1(i&ii)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_opasswd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_opasswd.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_opasswd.matched is defined and find_opasswd.matched > 0
tags:
- CCE-85728-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030030
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4).1(i&ii)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_opasswd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the opasswd rule in rules.d when on x86
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85728-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030030
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4).1(i&ii)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_opasswd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the opasswd rule in /etc/audit/audit.rules
lineinfile:
line: -w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification
state: present
dest: /etc/audit/audit.rules
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85728-4
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030030
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4).1(i&ii)
- NIST-800-53-AU-12.1(iv)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_opasswd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Events that Modify User/Group Information - /etc/passwd
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d , in order to capture events that modify
account changes:
-w /etc/passwd -p wa -k audit_rules_usergroup_modification
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file, in order to capture events that modify
account changes:
-w /etc/passwd -p wa -k audit_rules_usergroup_modification Rationale:In addition to auditing new user and group accounts, these watches
will alert the system administrator(s) to any modifications. Any unexpected
users, groups, or modifications should be investigated for legitimacy. Identifiers:
CCE-85577-5 References:
4.1.4, 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000169, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-3 R2.2.2, CIP-004-3 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SRG-OS-000274-GPOS-00104, SRG-OS-000275-GPOS-00105, SRG-OS-000276-GPOS-00106, SRG-OS-000277-GPOS-00107, SLES-15-030000, SV-234899r622137_rule, SRG-OS-000004-VMM-000040, SRG-OS-000239-VMM-000810, SRG-OS-000240-VMM-000820, SRG-OS-000241-VMM-000830, SRG-OS-000274-VMM-000960, SRG-OS-000275-VMM-000970, SRG-OS-000276-VMM-000980, SRG-OS-000277-VMM-000990, SRG-OS-000303-VMM-001090, SRG-OS-000304-VMM-001100, SRG-OS-000476-VMM-001960 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85577-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030000
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_passwd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit passwd tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85577-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030000
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_passwd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other user/group modification audit rules
find:
paths: /etc/audit/rules.d
recurse: false
contains: -k audit_rules_usergroup_modification$
patterns: '*.rules'
register: find_passwd
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85577-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030000
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_passwd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: If existing user/group modification ruleset not found, use /etc/audit/rules.d/privileged.rules
as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/privileged.rules
when:
- '"audit" in ansible_facts.packages'
- find_passwd.matched is defined and find_passwd.matched == 0
tags:
- CCE-85577-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030000
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_passwd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_passwd.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_passwd.matched is defined and find_passwd.matched > 0
tags:
- CCE-85577-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030000
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_passwd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the passwd rule in rules.d when on x86
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/passwd -p wa -k audit_rules_usergroup_modification
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85577-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030000
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_passwd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the passwd rule in /etc/audit/audit.rules
lineinfile:
line: -w /etc/passwd -p wa -k audit_rules_usergroup_modification
state: present
dest: /etc/audit/audit.rules
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85577-5
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030000
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_passwd
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Record Events that Modify User/Group Information - /etc/shadow
[ref]ruleIf the auditd daemon is configured to use the
augenrules program to read audit rules during daemon startup (the
default), add the following lines to a file with suffix .rules in the
directory /etc/audit/rules.d , in order to capture events that modify
account changes:
-w /etc/shadow -p wa -k audit_rules_usergroup_modification
If the auditd daemon is configured to use the auditctl
utility to read audit rules during daemon startup, add the following lines to
/etc/audit/audit.rules file, in order to capture events that modify
account changes:
-w /etc/shadow -p wa -k audit_rules_usergroup_modification Rationale:In addition to auditing new user and group accounts, these watches
will alert the system administrator(s) to any modifications. Any unexpected
users, groups, or modifications should be investigated for legitimacy. Identifiers:
CCE-85579-1 References:
4.1.4, 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000169, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-3 R2.2.2, CIP-004-3 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SLES-15-030020, SV-234901r622137_rule, SRG-OS-000004-VMM-000040, SRG-OS-000239-VMM-000810, SRG-OS-000240-VMM-000820, SRG-OS-000241-VMM-000830, SRG-OS-000274-VMM-000960, SRG-OS-000275-VMM-000970, SRG-OS-000276-VMM-000980, SRG-OS-000277-VMM-000990, SRG-OS-000303-VMM-001090, SRG-OS-000304-VMM-001100, SRG-OS-000476-VMM-001960 Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Reboot: | true |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85579-1
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030020
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_shadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Set architecture for audit shadow tasks
set_fact:
audit_arch: b{{ ansible_architecture | regex_replace('.*(\d\d$)','\1') }}
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85579-1
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030020
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_shadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Search /etc/audit/rules.d for other user/group modification audit rules
find:
paths: /etc/audit/rules.d
recurse: false
contains: -k audit_rules_usergroup_modification$
patterns: '*.rules'
register: find_shadow
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85579-1
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030020
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_shadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: If existing user/group modification ruleset not found, use /etc/audit/rules.d/privileged.rules
as the recipient for the rule
set_fact:
all_files:
- /etc/audit/rules.d/privileged.rules
when:
- '"audit" in ansible_facts.packages'
- find_shadow.matched is defined and find_shadow.matched == 0
tags:
- CCE-85579-1
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030020
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_shadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Use matched file as the recipient for the rule
set_fact:
all_files:
- '{{ find_shadow.files | map(attribute=''path'') | list | first }}'
when:
- '"audit" in ansible_facts.packages'
- find_shadow.matched is defined and find_shadow.matched > 0
tags:
- CCE-85579-1
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030020
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_shadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the shadow rule in rules.d when on x86
lineinfile:
path: '{{ all_files[0] }}'
line: -w /etc/shadow -p wa -k audit_rules_usergroup_modification
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85579-1
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030020
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_shadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
- name: Inserts/replaces the shadow rule in /etc/audit/audit.rules
lineinfile:
line: -w /etc/shadow -p wa -k audit_rules_usergroup_modification
state: present
dest: /etc/audit/audit.rules
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85579-1
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030020
- NIST-800-171-3.1.7
- NIST-800-53-AC-2(4)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-2(d)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.2.5
- audit_rules_usergroup_modification_shadow
- low_complexity
- low_disruption
- medium_severity
- reboot_required
- restrict_strategy
|
Configure auditd Data Retention
[ref]groupThe audit system writes data to /var/log/audit/audit.log . By default,
auditd rotates 5 logs by size (6MB), retaining a maximum of 30MB of
data in total, and refuses to write entries when the disk is too
full. This minimizes the risk of audit data filling its partition
and impacting other services. This also minimizes the risk of the audit
daemon temporarily disabling the system if it cannot write audit log (which
it can be configured to do).
For a busy
system or a system which is thoroughly auditing system activity, the default settings
for data retention may be
insufficient. The log file size needed will depend heavily on what types
of events are being audited. First configure auditing to log all the events of
interest. Then monitor the log size manually for awhile to determine what file
size will allow you to keep the required data for the correct time period.
Using a dedicated partition for /var/log/audit prevents the
auditd logs from disrupting system functionality if they fill, and,
more importantly, prevents other activity in /var from filling the
partition and stopping the audit trail. (The audit logs are size-limited and
therefore unlikely to grow without bound unless configured to do so.) Some
machines may have requirements that no actions occur which cannot be audited.
If this is the case, then auditd can be configured to halt the machine
if it runs out of space. Note: Since older logs are rotated,
configuring auditd this way does not prevent older logs from being
rotated away before they can be viewed.
If your system is configured to halt when logging cannot be performed, make
sure this can never happen under normal circumstances! Ensure that
/var/log/audit is on its own partition, and that this partition is
larger than the maximum amount of data auditd will retain
normally. |
contains 7 rules |
Configure a Sufficiently Large Partition for Audit Logs
[ref]ruleThe SUSE Linux Enterprise 15 operating system must allocate audit record storage
capacity to store at least one weeks worth of audit records when audit
records are not immediately sent to a central audit record storage
facility.
The partition size needed to capture a week's worth of audit records is
based on the activity level of the system and the total storage capacity
available. In normal circumstances, 10.0 GB of storage space for audit
records will be sufficient.
Determine which partition the audit records are being written to with the
following command:
# grep log_file /etc/audit/auditd.conf
log_file = /var/log/audit/audit.log
Check the size of the partition that audit records are written to with the
following command:
# df -h /var/log/audit/
/dev/sda2 24G 10.4G 13.6G 43% /var/log/audit Rationale:Information stored in one location is vulnerable to accidental or incidental
deletion or alteration.Off-loading is a common process in information
systems with limited audit storage capacity. |
Configure audispd's Plugin disk_full_action When Disk Is Full
[ref]ruleConfigure the action the operating system takes if the disk the audit records
are written to becomes full. Edit the file /etc/audisp/audisp-remote.conf .
Add or modify the following line, substituting ACTION appropriately:
disk_full_action = ACTION
Set this value to single to cause the system to switch to single user
mode for corrective action. Acceptable values also include syslog and
halt . For certain systems, the need for availability
outweighs the need to log all actions, and a different setting should be
determined.Rationale:Taking appropriate action in case of a filled audit storage volume will
minimize the possibility of losing audit records. |
Encrypt Audit Records Sent With audispd Plugin
[ref]ruleConfigure the operating system to encrypt the transfer of off-loaded audit
records onto a different system or media from the system being audited.
Uncomment the enable_krb5 option in /etc/audisp/audisp-remote.conf ,
and set it with the following line:
enable_krb5 = yes Rationale:Information stored in one location is vulnerable to accidental or incidental deletion
or alteration. Off-loading is a common process in information systems with limited
audit storage capacity. Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
AUDISP_REMOTE_CONFIG="/etc/audisp/audisp-remote.conf"
option="^enable_krb5"
value="yes"
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "$AUDISP_REMOTE_CONFIG"; then
sed_command+=('--follow-symlinks')
fi
# If the cce arg is empty, CCE is not assigned.
if [ -z "CCE-85614-6" ]; then
cce="CCE"
else
cce="CCE-85614-6"
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "$option")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$value"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "$option\\>" "$AUDISP_REMOTE_CONFIG"; then
"${sed_command[@]}" "s/$option\\>.*/$formatted_output/gi" "$AUDISP_REMOTE_CONFIG"
else
# \n is precaution for case where file ends without trailing newline
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "$AUDISP_REMOTE_CONFIG" >> "$AUDISP_REMOTE_CONFIG"
printf '%s\n' "$formatted_output" >> "$AUDISP_REMOTE_CONFIG"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85614-6
- DISA-STIG-SLES-15-030680
- NIST-800-53-AU-9(3)
- NIST-800-53-CM-6(a)
- auditd_audispd_encrypt_sent_records
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Configure Kerberos 5 Encryption in Audit Event Multiplexor (audispd)
lineinfile:
dest: /etc/audisp/audisp-remote.conf
line: enable_krb5 = yes
regexp: ^\s*enable_krb5\s*=\s*.*$
state: present
mode: 416
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85614-6
- DISA-STIG-SLES-15-030680
- NIST-800-53-AU-9(3)
- NIST-800-53-CM-6(a)
- auditd_audispd_encrypt_sent_records
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
|
Configure audispd's Plugin network_failure_action On Network Failure
[ref]ruleConfigure the action the operating system takes if there is an error sending
audit records to a remote system. Edit the file /etc/audisp/audisp-remote.conf .
Add or modify the following line, substituting ACTION appropriately:
network_failure_action = ACTION
Set this value to single to cause the system to switch to single user
mode for corrective action. Acceptable values also include syslog and
halt . For certain systems, the need for availability
outweighs the need to log all actions, and a different setting should be
determined.
This profile configures the action to be single .Rationale:Taking appropriate action when there is an error sending audit records to a
remote system will minimize the possibility of losing audit records. |
Configure auditd Disk Full Action when Disk Space Is Full
[ref]ruleThe auditd service can be configured to take an action
when disk space is running low but prior to running out of space completely.
Edit the file /etc/audit/auditd.conf . Add or modify the following line,
substituting ACTION appropriately:
disk_full_action = ACTION
Set this value to single to cause the system to switch to single-user
mode for corrective action. Acceptable values also include syslog ,
single , and halt . For certain systems, the need for availability
outweighs the need to log all actions, and a different setting should be
determined. Details regarding all possible values for ACTION are described in the
auditd.conf man page.Rationale:Taking appropriate action in case of a filled audit storage volume will minimize
the possibility of losing audit records. Identifiers:
CCE-85606-2 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, APO11.04, APO12.06, APO13.01, BAI03.05, BAI04.04, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, MEA02.01, CCI-000140, 4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 7.1, SR 7.2, A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.16.1.4, A.16.1.5, A.16.1.7, A.17.2.1, AU-5(b), AU-5(2), AU-5(1), AU-5(4), CM-6(a), DE.AE-3, DE.AE-5, PR.DS-4, PR.PT-1, RS.AN-1, RS.AN-4, SRG-OS-000047-GPOS-00023, SLES-15-030590, SV-234958r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
var_auditd_disk_full_action="syslog"
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/audit/auditd.conf"; then
sed_command+=('--follow-symlinks')
fi
# If the cce arg is empty, CCE is not assigned.
if [ -z "CCE-85606-2" ]; then
cce="CCE"
else
cce="CCE-85606-2"
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^disk_full_action")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_auditd_disk_full_action"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^disk_full_action\\>" "/etc/audit/auditd.conf"; then
"${sed_command[@]}" "s/^disk_full_action\\>.*/$formatted_output/gi" "/etc/audit/auditd.conf"
else
# \n is precaution for case where file ends without trailing newline
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/audit/auditd.conf" >> "/etc/audit/auditd.conf"
printf '%s\n' "$formatted_output" >> "/etc/audit/auditd.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85606-2
- DISA-STIG-SLES-15-030590
- NIST-800-53-AU-5(1)
- NIST-800-53-AU-5(2)
- NIST-800-53-AU-5(4)
- NIST-800-53-AU-5(b)
- NIST-800-53-CM-6(a)
- auditd_data_disk_full_action
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_auditd_disk_full_action # promote to variable
set_fact:
var_auditd_disk_full_action: !!str syslog
tags:
- always
- name: Configure auditd Disk Full Action when Disk Space Is Full
lineinfile:
dest: /etc/audit/auditd.conf
line: disk_full_action = {{ var_auditd_disk_full_action }}
regexp: ^\s*disk_full_action\s*=\s*.*$
state: present
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85606-2
- DISA-STIG-SLES-15-030590
- NIST-800-53-AU-5(1)
- NIST-800-53-AU-5(2)
- NIST-800-53-AU-5(4)
- NIST-800-53-AU-5(b)
- NIST-800-53-CM-6(a)
- auditd_data_disk_full_action
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Configure auditd mail_acct Action on Low Disk Space
[ref]ruleThe auditd service can be configured to send email to
a designated account in certain situations. Add or correct the following line
in /etc/audit/auditd.conf to ensure that administrators are notified
via email for those situations:
action_mail_acct = root Rationale:Email sent to the root account is typically aliased to the
administrators of the system, who can take appropriate action. Identifiers:
CCE-85604-7 References:
4.1.2.3, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO11.04, APO12.06, APO13.01, BAI03.05, BAI04.04, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, MEA02.01, 3.3.1, CCI-000139, CCI-001855, 164.312(a)(2)(ii), 4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 7.1, SR 7.2, A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.16.1.4, A.16.1.5, A.16.1.7, A.17.2.1, CIP-003-3 R1.3, CIP-003-3 R3, CIP-003-3 R3.1, CIP-003-3 R3.2, CIP-003-3 R3.3, CIP-003-3 R5.1.1, CIP-003-3 R5.3, CIP-004-3 R2.2.3, CIP-004-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, IA-5(1), AU-5(a), AU-5(2), CM-6(a), DE.AE-3, DE.AE-5, PR.DS-4, PR.PT-1, RS.AN-1, RS.AN-4, Req-10.7.a, SRG-OS-000046-GPOS-00022, SRG-OS-000343-GPOS-00134, SLES-15-030570, SV-234956r622137_rule, SRG-OS-000046-VMM-000210, SRG-OS-000343-VMM-001240 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
var_auditd_action_mail_acct="root"
AUDITCONFIG=/etc/audit/auditd.conf
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "$AUDITCONFIG"; then
sed_command+=('--follow-symlinks')
fi
# If the cce arg is empty, CCE is not assigned.
if [ -z "CCE-85604-7" ]; then
cce="CCE"
else
cce="CCE-85604-7"
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^action_mail_acct")
# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_auditd_action_mail_acct"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^action_mail_acct\\>" "$AUDITCONFIG"; then
"${sed_command[@]}" "s/^action_mail_acct\\>.*/$formatted_output/gi" "$AUDITCONFIG"
else
# \n is precaution for case where file ends without trailing newline
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "$AUDITCONFIG" >> "$AUDITCONFIG"
printf '%s\n' "$formatted_output" >> "$AUDITCONFIG"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85604-7
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030570
- NIST-800-171-3.3.1
- NIST-800-53-AU-5(2)
- NIST-800-53-AU-5(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)
- PCI-DSS-Req-10.7.a
- auditd_data_retention_action_mail_acct
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_auditd_action_mail_acct # promote to variable
set_fact:
var_auditd_action_mail_acct: !!str root
tags:
- always
- name: Configure auditd mail_acct Action on Low Disk Space
lineinfile:
dest: /etc/audit/auditd.conf
line: action_mail_acct = {{ var_auditd_action_mail_acct }}
state: present
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85604-7
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030570
- NIST-800-171-3.3.1
- NIST-800-53-AU-5(2)
- NIST-800-53-AU-5(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(1)
- PCI-DSS-Req-10.7.a
- auditd_data_retention_action_mail_acct
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Configure auditd space_left on Low Disk Space
[ref]ruleThe auditd service can be configured to take an action
when disk space is running low but prior to running out of space completely.
Edit the file /etc/audit/auditd.conf . Add or modify the following line,
substituting SIZE_in_MB appropriately:
space_left = SIZE_in_MB
Set this value to the appropriate size in Megabytes cause the system to
notify the user of an issue.Rationale:Notifying administrators of an impending disk space problem may allow them to
take corrective action prior to any disruption. Identifiers:
CCE-85616-1 References:
1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, APO11.04, APO12.06, APO13.01, BAI03.05, BAI04.04, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, MEA02.01, CCI-001855, 4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 7.1, SR 7.2, A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.16.1.4, A.16.1.5, A.16.1.7, A.17.2.1, AU-5(b), AU-5(2), AU-5(1), AU-5(4), CM-6(a), DE.AE-3, DE.AE-5, PR.DS-4, PR.PT-1, RS.AN-1, RS.AN-4, Req-10.7, SRG-OS-000343-GPOS-00134, SLES-15-030700, SV-234969r622137_rule, SRG-OS-000343-VMM-001240 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q audit; then
var_auditd_space_left="100"
grep -q "^space_left[[:space:]]*=.*$" /etc/audit/auditd.conf && \
sed -i "s/^space_left[[:space:]]*=.*$/space_left = $var_auditd_space_left/g" /etc/audit/auditd.conf || \
echo "space_left = $var_auditd_space_left" >> /etc/audit/auditd.conf
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85616-1
- DISA-STIG-SLES-15-030700
- NIST-800-53-AU-5(1)
- NIST-800-53-AU-5(2)
- NIST-800-53-AU-5(4)
- NIST-800-53-AU-5(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.7
- auditd_data_retention_space_left
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_auditd_space_left # promote to variable
set_fact:
var_auditd_space_left: !!str 100
tags:
- always
- name: Configure auditd space_left on Low Disk Space
lineinfile:
dest: /etc/audit/auditd.conf
line: space_left = {{ var_auditd_space_left }}
regexp: ^\s*space_left\s*=\s*.*$
state: present
create: true
when: '"audit" in ansible_facts.packages'
tags:
- CCE-85616-1
- DISA-STIG-SLES-15-030700
- NIST-800-53-AU-5(1)
- NIST-800-53-AU-5(2)
- NIST-800-53-AU-5(4)
- NIST-800-53-AU-5(b)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-10.7
- auditd_data_retention_space_left
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure the default plugins for the audit dispatcher are Installed
[ref]ruleThe audit-audispd-plugins package should be installed. Rationale:Information stored in one location is vulnerable to accidental or incidental deletion or alteration. Off-loading is a common process in information systems with limited audit storage capacity. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
zypper install -y "audit-audispd-plugins"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
- name: Ensure audit-audispd-plugins is installed
package:
name: audit-audispd-plugins
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85613-8
- DISA-STIG-SLES-15-030670
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_audit-audispd-plugins_installed
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include install_audit-audispd-plugins
class install_audit-audispd-plugins {
package { 'audit-audispd-plugins':
ensure => 'installed',
}
}
Remediation script: (show)
[[packages]]
name = "audit-audispd-plugins"
version = "*"
|
Ensure the audit Subsystem is Installed
[ref]ruleThe audit package should be installed. Rationale:The auditd service is an access monitoring and accounting daemon, watching system calls to audit any access, in comparison with potential local access control policy such as SELinux policy. Identifiers:
CCE-85612-0 References:
BP28(R50), 4.1.1.1, CCI-000172, CCI-001814, CCI-001875, CCI-001877, CCI-001878, CCI-001879, CCI-001880, CCI-001881, CCI-001882, CCI-001889, CCI-001914, CCI-000169, CIP-004-3 R3.3, CIP-007-3 R6.5, AC-7(a), AU-7(1), AU-7(2), AU-14, AU-12(2), AU-2(a), CM-6(a), SRG-OS-000122-GPOS-00063, SRG-OS-000337-GPOS-00129, SRG-OS-000348-GPOS-00136, SRG-OS-000349-GPOS-00137, SRG-OS-000350-GPOS-00138, SRG-OS-000351-GPOS-00139, SRG-OS-000352-GPOS-00140, SRG-OS-000353-GPOS-00141, SRG-OS-000354-GPOS-00142, SRG-OS-000358-GPOS-00145, SRG-OS-000359-GPOS-00146, SRG-OS-000365-GPOS-00152, SRG-OS-000474-GPOS-00219, SRG-OS-000475-GPOS-00220, SRG-OS-000480-GPOS-00227, SRG-OS-000062-GPOS-00031, SLES-15-030650, SV-234964r622137_rule Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
zypper install -y "audit"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
- name: Ensure audit is installed
package:
name: audit
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85612-0
- DISA-STIG-SLES-15-030650
- NIST-800-53-AC-7(a)
- NIST-800-53-AU-12(2)
- NIST-800-53-AU-14
- NIST-800-53-AU-2(a)
- NIST-800-53-AU-7(1)
- NIST-800-53-AU-7(2)
- NIST-800-53-CM-6(a)
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_audit_installed
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include install_audit
class install_audit {
package { 'audit':
ensure => 'installed',
}
}
Remediation script: (show)
[[packages]]
name = "audit"
version = "*"
|
Enable auditd Service
[ref]ruleThe auditd service is an essential userspace component of
the Linux Auditing System, as it is responsible for writing audit records to
disk.
The auditd service can be enabled with the following command:
$ sudo systemctl enable auditd.service Rationale:Without establishing what type of events occurred, it would be difficult
to establish, correlate, and investigate the events leading up to an outage or attack.
Ensuring the auditd service is active ensures audit records
generated by the kernel are appropriately recorded.
Additionally, a properly configured audit subsystem ensures that actions of
individual system users can be uniquely traced to those users so they
can be held accountable for their actions. Identifiers:
CCE-85581-7 References:
4.1.1.2, 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.3.1, 3.3.2, 3.3.6, CCI-000126, CCI-000130, CCI-000131, CCI-000132, CCI-000133, CCI-000134, CCI-000135, CCI-000154, CCI-000158, CCI-000366, CCI-001464, CCI-001487, CCI-001814, CCI-001876, CCI-002884, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(5)(ii)(C), 164.310(a)(2)(iv), 164.310(d)(2)(iii), 164.312(b), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, CIP-004-3 R3.3, CIP-007-3 R6.5, AC-2(g), AU-3, AU-10, AU-2(d), AU-12(c), AU-14(1), AC-6(9), CM-6(a), SI-4(23), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.1, SRG-OS-000037-GPOS-00015, SRG-OS-000038-GPOS-00016, SRG-OS-000039-GPOS-00017, SRG-OS-000040-GPOS-00018, SRG-OS-000041-GPOS-00019, SRG-OS-000042-GPOS-00021, SRG-OS-000051-GPOS-00024, SRG-OS-000054-GPOS-00025, SRG-OS-000122-GPOS-00063, SRG-OS-000254-GPOS-00095, SRG-OS-000255-GPOS-00096, SRG-OS-000365-GPOS-00152, SRG-OS-000392-GPOS-00172, SRG-OS-000480-GPOS-00227, SRG-OS-000062-GPOS-00031, SLES-15-030050, SV-234904r622137_rule, SRG-OS-000037-VMM-000150, SRG-OS-000063-VMM-000310, SRG-OS-000038-VMM-000160, SRG-OS-000039-VMM-000170, SRG-OS-000040-VMM-000180, SRG-OS-000041-VMM-000190 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q audit; }; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" unmask 'auditd.service'
"$SYSTEMCTL_EXEC" start 'auditd.service'
"$SYSTEMCTL_EXEC" enable 'auditd.service'
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-85581-7
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030050
- NIST-800-171-3.3.1
- NIST-800-171-3.3.2
- NIST-800-171-3.3.6
- NIST-800-53-AC-2(g)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-10
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-14(1)
- NIST-800-53-AU-2(d)
- NIST-800-53-AU-3
- NIST-800-53-CM-6(a)
- NIST-800-53-SI-4(23)
- PCI-DSS-Req-10.1
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_auditd_enabled
- name: Enable service auditd
block:
- name: Gather the package facts
package_facts:
manager: auto
- name: Enable service auditd
service:
name: auditd
enabled: 'yes'
state: started
masked: 'no'
when:
- '"audit" in ansible_facts.packages'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"audit" in ansible_facts.packages'
tags:
- CCE-85581-7
- CJIS-5.4.1.1
- DISA-STIG-SLES-15-030050
- NIST-800-171-3.3.1
- NIST-800-171-3.3.2
- NIST-800-171-3.3.6
- NIST-800-53-AC-2(g)
- NIST-800-53-AC-6(9)
- NIST-800-53-AU-10
- NIST-800-53-AU-12(c)
- NIST-800-53-AU-14(1)
- NIST-800-53-AU-2(d)
- NIST-800-53-AU-3
- NIST-800-53-CM-6(a)
- NIST-800-53-SI-4(23)
- PCI-DSS-Req-10.1
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_auditd_enabled
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include enable_auditd
class enable_auditd {
service {'auditd':
enable => true,
ensure => 'running',
}
}
|
AppArmor
[ref]groupMany security vulnerabilities result from bugs in trusted programs. A trusted
program runs with privileges that attackers want to possess. The program fails
to keep that trust if there is a bug in the program that allows the attacker to
acquire said privilege.
AppArmor® is an application security solution designed specifically to apply
privilege confinement to suspect programs. AppArmor allows the administrator to
specify the domain of activities the program can perform by developing a
security profile. A security profile is a listing of files that the program may
access and the operations the program may perform. AppArmor secures
applications by enforcing good application behavior without relying on attack
signatures, so it can prevent attacks even if previously unknown
vulnerabilities are being exploited.
For more information on using AppArmor, see
https://www.suse.com/documentation/sles-12/book_security/data/cha_apparmor_intro.html. |
contains 2 rules |
Install the pam_apparmor Package
[ref]ruleThe pam_apparmor package can be installed with the following command:
$ sudo zypper install pam_apparmor Rationale:Protection of system integrity using AppArmor depends on this package being
installed. Identifiers:
CCE-85765-6 References:
1.7.1.1, CCI-001764, CCI-001774, CCI-002165, CCI-002233, CCI-002235, AC-3(4), AC-6(8), AC-6(10), CM-7(5)(b), CM-7(2), SC-7(21), CM-6(a), SRG-OS-000312-GPOS-00122, SRG-OS-000312-GPOS-00123SRG-OS-000312-GPOS-00124, SRG-OS-000324-GPOS-00125, SRG-OS-000326-GPOS-00126, SRG-OS-000370-GPOS-00155, SRG-OS-000480-GPOS-00230, SRG-OS-000480-GPOS-00227, SRG-OS-000480-GPOS-00231, SRG-OS-000480-GPOS-00232, SLES-15-010390, SV-234848r622137_rule Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
zypper install -y "pam_apparmor"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
- name: Ensure pam_apparmor is installed
package:
name: pam_apparmor
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85765-6
- DISA-STIG-SLES-15-010390
- NIST-800-53-AC-3(4)
- NIST-800-53-AC-6(10)
- NIST-800-53-AC-6(8)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(2)
- NIST-800-53-CM-7(5)(b)
- NIST-800-53-SC-7(21)
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_pam_apparmor_installed
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include install_pam_apparmor
class install_pam_apparmor {
package { 'pam_apparmor':
ensure => 'installed',
}
}
Remediation script: (show)
[[packages]]
name = "pam_apparmor"
version = "*"
|
Ensure AppArmor is Active and Configured
[ref]ruleVerify that the Apparmor tool is configured to
control whitelisted applications and user home directory access
control.
The apparmor service can be enabled with the following command:
$ sudo systemctl enable apparmor.service Rationale:Using a whitelist provides a configuration management method for allowing
the execution of only authorized software. Using only authorized software
decreases risk by limiting the number of potential vulnerabilities.
The organization must identify authorized software programs and permit
execution of authorized software by adding each authorized program to the
"pam_apparmor" exception policy. The process used to identify software
programs that are authorized to execute on organizational information
systems is commonly referred to as whitelisting.
Verification of whitelisted software occurs prior to execution or at system
startup.
Users' home directories/folders may contain information of a sensitive
nature. Nonprivileged users should coordinate any sharing of information
with a System Administrator (SA) through shared resources.
Apparmor can confine users to their home directory, not allowing them to
make any changes outside of their own home directories. Confining users to
their home directory will minimize the risk of sharing information. Identifiers:
CCE-85752-4 References:
1.7.1.2, CCI-001764, CCI-001774, CCI-002165, CCI-002233, CCI-002235, AC-3(4), AC-6(8), AC-6(10), CM-7(5)(b), CM-7(2), SC-7(21), CM-6(a), SRG-OS-000312-GPOS-00122, SRG-OS-000312-GPOS-00123SRG-OS-000312-GPOS-00124, SRG-OS-000324-GPOS-00125, SRG-OS-000326-GPOS-00126, SRG-OS-000370-GPOS-00155, SRG-OS-000480-GPOS-00230, SRG-OS-000480-GPOS-00227, SRG-OS-000480-GPOS-00231, SRG-OS-000480-GPOS-00232, SLES-15-010390, SV-234848r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
# Enable apparmor
/usr/bin/systemctl enable "apparmor"
/usr/bin/systemctl start "apparmor"
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
/usr/bin/systemctl reset-failed "apparmor"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
- name: Start apparmor.service
systemd:
name: apparmor.service
state: started
enabled: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85752-4
- DISA-STIG-SLES-15-010390
- NIST-800-53-AC-3(4)
- NIST-800-53-AC-6(10)
- NIST-800-53-AC-6(8)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(2)
- NIST-800-53-CM-7(5)(b)
- NIST-800-53-SC-7(21)
- apparmor_configured
- medium_severity
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include enable_apparmor
class enable_apparmor {
service {'apparmor':
enable => true,
ensure => 'running',
}
}
|
GRUB2 bootloader configuration
[ref]groupDuring the boot process, the boot loader is
responsible for starting the execution of the kernel and passing
options to it. The boot loader allows for the selection of
different kernels - possibly on different partitions or media.
The default SUSE Linux Enterprise 15 boot loader for x86 systems is called GRUB2.
Options it can pass to the kernel include single-user mode, which
provides root access without any authentication, and the ability to
disable SELinux. To prevent local users from modifying the boot
parameters and endangering security, protect the boot loader configuration
with a password and ensure its configuration file's permissions
are set properly. |
contains 2 rules |
Non-UEFI GRUB2 bootloader configuration
[ref]groupNon-UEFI GRUB2 bootloader configuration |
contains 1 rule |
Set Boot Loader Password in grub2
[ref]ruleThe grub2 boot loader should have a superuser account and password
protection enabled to protect boot-time settings.
Since plaintext passwords are a security risk, generate a hash for the password
by running the following command:
$ grub2-mkpasswd-pbkdf2
When prompted, enter the password that was selected.
Using the hash from the output, modify the /etc/grub.d/40_custom
file with the following content:
set superusers="boot"
password_pbkdf2 boot grub.pbkdf2.sha512.VeryLongString
NOTE: the bootloader superuser account and password MUST differ from the
root account and password.
Once the superuser password has been added,
update the
grub.cfg file by running:
grub2-mkconfig -o /boot/grub2/grub.cfg Warning:
To prevent hard-coded passwords, automatic remediation of this control is not available. Remediation
must be automated as a component of machine provisioning, or followed manually as outlined above.
Also, do NOT manually add the superuser account and password to the
grub.cfg file as the grub2-mkconfig command overwrites this file. Rationale:Password protection on the boot loader configuration ensures
users with physical access cannot trivially alter
important bootloader settings. These include which kernel to use,
and whether to enter single-user mode. Identifiers:
CCE-83274-1 References:
BP28(R17), 1.5.1, 1, 11, 12, 14, 15, 16, 18, 3, 5, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.06, DSS06.10, 3.4.5, CCI-000213, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, A.18.1.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CM-6(a), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.PT-3, FIA_UAU.1, SRG-OS-000080-GPOS-00048, SLES-15-010190, SV-234819r622137_rule |
UEFI GRUB2 bootloader configuration
[ref]groupUEFI GRUB2 bootloader configuration |
contains 1 rule |
Set the UEFI Boot Loader Password
[ref]ruleThe grub2 boot loader should have a superuser account and password
protection enabled to protect boot-time settings.
Since plaintext passwords are a security risk, generate a hash for the password
by running the following command:
$ grub2-mkpasswd-pbkdf2
When prompted, enter the password that was selected.
Using the hash from the output, modify the /etc/grub.d/40_custom
file with the following content:
set superusers="boot"
password_pbkdf2 boot grub.pbkdf2.sha512.VeryLongString
NOTE: the bootloader superuser account and password MUST differ from the
root account and password.
Once the superuser password has been added,
update the
grub.cfg file by running:
grub2-mkconfig -o /boot/grub2/grub.cfg Warning:
To prevent hard-coded passwords, automatic remediation of this control is not available. Remediation
must be automated as a component of machine provisioning, or followed manually as outlined above.
Also, do NOT manually add the superuser account and password to the
grub.cfg file as the grub2-mkconfig command overwrites this file. Rationale:Password protection on the boot loader configuration ensures
users with physical access cannot trivially alter
important bootloader settings. These include which kernel to use,
and whether to enter single-user mode. Identifiers:
CCE-83275-8 References:
BP28(R17), 1.5.1, 11, 12, 14, 15, 16, 18, 3, 5, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.03, DSS06.06, 3.4.5, CCI-000213, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), PR.AC-4, PR.AC-6, PR.PT-3, FIA_UAU.1, SRG-OS-000080-GPOS-00048, SLES-15-010200, SV-234820r622137_rule |
Configure Syslog
[ref]groupThe syslog service has been the default Unix logging mechanism for
many years. It has a number of downsides, including inconsistent log format,
lack of authentication for received messages, and lack of authentication,
encryption, or reliable transport for messages sent over a network. However,
due to its long history, syslog is a de facto standard which is supported by
almost all Unix applications.
In SUSE Linux Enterprise 15, rsyslog has replaced ksyslogd as the
syslog daemon of choice, and it includes some additional security features
such as reliable, connection-oriented (i.e. TCP) transmission of logs, the
option to log to database formats, and the encryption of log data en route to
a central logging server.
This section discusses how to configure rsyslog for
best effect, and how to use tools provided with the system to maintain and
monitor logs. |
contains 2 rules |
Rsyslog Logs Sent To Remote Host
[ref]groupIf system logs are to be useful in detecting malicious
activities, it is necessary to send logs to a remote server. An
intruder who has compromised the root account on a system may
delete the log entries which indicate that the system was attacked
before they are seen by an administrator.
However, it is recommended that logs be stored on the local
host in addition to being sent to the loghost, especially if
rsyslog has been configured to use the UDP protocol to send
messages over a network. UDP does not guarantee reliable delivery,
and moderately busy sites will lose log messages occasionally,
especially in periods of high traffic which may be the result of an
attack. In addition, remote rsyslog messages are not
authenticated in any way by default, so it is easy for an attacker to
introduce spurious messages to the central log server. Also, some
problems cause loss of network connectivity, which will prevent the
sending of messages to the central server. For all of these reasons, it is
better to store log messages both centrally and on each host, so
that they can be correlated if necessary. |
contains 1 rule |
Ensure Logs Sent To Remote Host
[ref]ruleTo configure rsyslog to send logs to a remote log server,
open /etc/rsyslog.conf and read and understand the last section of the file,
which describes the multiple directives necessary to activate remote
logging.
Along with these other directives, the system can be configured
to forward its logs to a particular log server by
adding or correcting one of the following lines,
substituting logcollector appropriately.
The choice of protocol depends on the environment of the system;
although TCP and RELP provide more reliable message delivery,
they may not be supported in all environments.
To use UDP for log message delivery:
*.* @logcollector
To use TCP for log message delivery:
*.* @@logcollector
To use RELP for log message delivery:
*.* :omrelp:logcollector
There must be a resolvable DNS CNAME or Alias record set to "logcollector" for logs to be sent correctly to the centralized logging utility.Rationale:A log server (loghost) receives syslog messages from one or more
systems. This data can be used as an additional log source in the event a
system is compromised and its local logs are suspect. Forwarding log messages
to a remote loghost also provides system administrators with a centralized
place to view the status of multiple hosts within the enterprise. Identifiers:
CCE-85552-8 References:
BP28(R7), NT28(R43), NT12(R5), 4.2.1.5, 1, 13, 14, 15, 16, 2, 3, 5, 6, APO11.04, APO13.01, BAI03.05, BAI04.04, DSS05.04, DSS05.07, MEA02.01, CCI-000366, CCI-001348, CCI-000136, CCI-001851, 164.308(a)(1)(ii)(D), 164.308(a)(5)(ii)(B), 164.308(a)(5)(ii)(C), 164.308(a)(6)(ii), 164.308(a)(8), 164.310(d)(2)(iii), 164.312(b), 164.314(a)(2)(i)(C), 164.314(a)(2)(iii), 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 7.1, SR 7.2, 0988, 1405, A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.17.2.1, CIP-003-3 R5.2, CIP-004-3 R3.3, CM-6(a), AU-4(1), AU-9(2), PR.DS-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000479-GPOS-00224, SRG-OS-000480-GPOS-00227, SRG-OS-000342-GPOS-00133, SLES-15-010580, SV-234865r622137_rule, SRG-OS-000032-VMM-000130 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
rsyslog_remote_loghost_address="logcollector"
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/rsyslog.conf"; then
sed_command+=('--follow-symlinks')
fi
# If the cce arg is empty, CCE is not assigned.
if [ -z "CCE-85552-8" ]; then
cce="CCE"
else
cce="CCE-85552-8"
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^\*\.\*")
# shellcheck disable=SC2059
printf -v formatted_output "%s %s" "$stripped_key" "@@$rsyslog_remote_loghost_address"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^\*\.\*\\>" "/etc/rsyslog.conf"; then
"${sed_command[@]}" "s/^\*\.\*\\>.*/$formatted_output/gi" "/etc/rsyslog.conf"
else
# \n is precaution for case where file ends without trailing newline
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/rsyslog.conf" >> "/etc/rsyslog.conf"
printf '%s\n' "$formatted_output" >> "/etc/rsyslog.conf"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: XCCDF Value rsyslog_remote_loghost_address # promote to variable
set_fact:
rsyslog_remote_loghost_address: !!str logcollector
tags:
- always
- name: Set rsyslog remote loghost
lineinfile:
dest: /etc/rsyslog.conf
regexp: ^\*\.\*
line: '*.* @@{{ rsyslog_remote_loghost_address }}'
create: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85552-8
- DISA-STIG-SLES-15-010580
- NIST-800-53-AU-4(1)
- NIST-800-53-AU-9(2)
- NIST-800-53-CM-6(a)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- rsyslog_remote_loghost
|
Ensure real-time clock is set to UTC
[ref]ruleEnsure that the system real-time clock (RTC) is set to Coordinated Universal Time (UTC). Rationale:If time stamps are not consistently applied and there is no common
time reference, it is difficult to perform forensic analysis.
Time stamps generated by the operating system include date and time.
Time is commonly expressed in UTC, a modern continuation of GMT, or
local time with an offset from UTC. Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if timedatectl status | grep -i "time zone" | grep -iv 'UTC\|GMT'; then
timedatectl set-timezone UTC
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
- name: Check 'UTC' timezone is set
shell: |
set -o pipefail
timedatectl status | grep -i 'Time zone'| grep -iv 'UTC\|GMT' || true
register: check_tz
failed_when: check_tz.rc not in [ 0 , 1 ]
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85724-3
- DISA-STIG-SLES-15-010410
- NIST-800-53-AU-8(b)
- ensure_rtc_utc_configuration
- high_severity
- name: Configure OS to use 'UTC' timezone
command: timedatectl set-timezone UTC
become: true
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- check_tz.rc == 0
tags:
- CCE-85724-3
- DISA-STIG-SLES-15-010410
- NIST-800-53-AU-8(b)
- ensure_rtc_utc_configuration
- high_severity
|
Network Configuration and Firewalls
[ref]groupMost systems must be connected to a network of some
sort, and this brings with it the substantial risk of network
attack. This section discusses the security impact of decisions
about networking which must be made when configuring a system.
This section also discusses firewalls, network access
controls, and other network security frameworks, which allow
system-level rules to be written that can limit an attackers' ability
to connect to your system. These rules can specify that network
traffic should be allowed or denied from certain IP addresses,
hosts, and networks. The rules can also specify which of the
system's network services are available to particular hosts or
networks. |
contains 18 rules |
firewalld
[ref]groupThe dynamic firewall daemon firewalld provides a
dynamically managed firewall with support for network “zones” to assign
a level of trust to a network and its associated connections and interfaces.
It has support for IPv4 and IPv6 firewall settings. It supports Ethernet
bridges and has a separation of runtime and permanent configuration options.
It also has an interface for services or applications to add firewall rules
directly.
A graphical configuration tool, firewall-config , is used to configure
firewalld , which in turn uses iptables tool to communicate
with Netfilter in the kernel which implements packet filtering.
The firewall service provided by firewalld is dynamic rather than
static because changes to the configuration can be made at anytime and are
immediately implemented. There is no need to save or apply the changes. No
unintended disruption of existing network connections occurs as no part of
the firewall has to be reloaded. |
contains 2 rules |
Inspect and Activate Default firewalld Rules
[ref]groupFirewalls can be used to separate networks into different zones
based on the level of trust the user has decided to place on the devices and
traffic within that network. NetworkManager informs firewalld to which
zone an interface belongs. An interface's assigned zone can be changed by
NetworkManager or via the firewall-config tool.
The zone settings in /etc/firewalld/ are a range of preset settings
which can be quickly applied to a network interface. These are the zones
provided by firewalld sorted according to the default trust level of the
zones from untrusted to trusted:
drop
Any incoming network packets are dropped, there is no
reply. Only outgoing network connections are possible. block
Any incoming network connections are rejected with an
icmp-host-prohibited message for IPv4 and icmp6-adm-prohibited
for IPv6. Only network connections initiated from within the system are
possible. public
For use in public areas. You do not trust the other
computers on the network to not harm your computer. Only selected incoming
connections are accepted. external
For use on external networks with masquerading enabled
especially for routers. You do not trust the other computers on the network to
not harm your computer. Only selected incoming connections are accepted. dmz
For computers in your demilitarized zone that are
publicly-accessible with limited access to your internal network. Only selected
incoming connections are accepted. work
For use in work areas. You mostly trust the other computers
on networks to not harm your computer. Only selected incoming connections are
accepted. home
For use in home areas. You mostly trust the other computers
on networks to not harm your computer. Only selected incoming connections are
accepted. internal
For use on internal networks. You mostly trust the
other computers on the networks to not harm your computer. Only selected
incoming connections are accepted. trusted
All network connections are accepted.
It is possible to designate one of these zones to be the default zone. When
interface connections are added to NetworkManager , they are assigned
to the default zone. On installation, the default zone in firewalld is set to
be the public zone.
To find out all the settings of a zone, for example the public zone,
enter the following command as root:
# firewall-cmd --zone=public --list-all
Example output of this command might look like the following:
# firewall-cmd --zone=public --list-all
public
interfaces:
services: mdns dhcpv6-client ssh
ports:
forward-ports:
icmp-blocks: source-quench
To view the network zones currently active, enter the following command as root:
# firewall-cmd --get-service
The following listing displays the result of this command
on common SUSE Linux Enterprise 15 system:
# firewall-cmd --get-service
amanda-client bacula bacula-client dhcp dhcpv6 dhcpv6-client dns ftp
high-availability http https imaps ipp ipp-client ipsec kerberos kpasswd
ldap ldaps libvirt libvirt-tls mdns mountd ms-wbt mysql nfs ntp openvpn
pmcd pmproxy pmwebapi pmwebapis pop3s postgresql proxy-dhcp radius rpc-bind
samba samba-client smtp ssh telnet tftp tftp-client transmission-client
vnc-server wbem-https
Finally to view the network zones that will be active after the next firewalld
service reload, enter the following command as root:
# firewall-cmd --get-service --permanent |
contains 2 rules |
Install firewalld Package
[ref]ruleThe firewalld package can be installed with the following command:
$ sudo zypper install firewalld Rationale:The firewalld package should be installed to provide access control methods. Identifiers:
CCE-85698-9 References:
3.5.1.1, CCI-002314, CM-7, CM-7.1(iii), CM-7(b), AC-17(1), SRG-OS-000096-GPOS-00050, SRG-OS-000297-GPOS-00115, SRG-OS-000298-GPOS-00116, SRG-OS-000480-GPOS-00227, SRG-OS-000480-GPOS-00232, SLES-15-010220, SV-234821r622137_rule Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
zypper install -y "firewalld"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
- name: Ensure firewalld is installed
package:
name: firewalld
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85698-9
- DISA-STIG-SLES-15-010220
- NIST-800-53-AC-17(1)
- NIST-800-53-CM-7
- NIST-800-53-CM-7(b)
- NIST-800-53-CM-7.1(iii)
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- package_firewalld_installed
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include install_firewalld
class install_firewalld {
package { 'firewalld':
ensure => 'installed',
}
}
Remediation script: (show)
[[packages]]
name = "firewalld"
version = "*"
|
Verify firewalld Enabled
[ref]rule
The firewalld service can be enabled with the following command:
$ sudo systemctl enable firewalld.service Rationale:Access control methods provide the ability to enhance system security posture
by restricting services and known good IP addresses and address ranges. This
prevents connections from unknown hosts and protocols. Identifiers:
CCE-85751-6 References:
3.5.1.4, 11, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.1.3, 3.4.7, CCI-000366, CCI-000382, CCI-002314, 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, CIP-003-3 R4, CIP-003-3 R5, CIP-004-3 R3, CM-7, CM-7.1(iii), CM-7(b), AC-17(1), PR.IP-1, FMT_MOF_EXT.1, SRG-OS-000096-GPOS-00050, SRG-OS-000297-GPOS-00115, SRG-OS-000480-GPOS-00227, SRG-OS-000480-GPOS-00231, SRG-OS-000480-GPOS-00232, SLES-15-010220, SV-234821r622137_rule Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" unmask 'firewalld.service'
"$SYSTEMCTL_EXEC" start 'firewalld.service'
"$SYSTEMCTL_EXEC" enable 'firewalld.service'
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
- name: Enable service firewalld
block:
- name: Gather the package facts
package_facts:
manager: auto
- name: Enable service firewalld
service:
name: firewalld
enabled: 'yes'
state: started
masked: 'no'
when:
- '"firewalld" in ansible_facts.packages'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85751-6
- DISA-STIG-SLES-15-010220
- NIST-800-171-3.1.3
- NIST-800-171-3.4.7
- NIST-800-53-AC-17(1)
- NIST-800-53-CM-7
- NIST-800-53-CM-7(b)
- NIST-800-53-CM-7.1(iii)
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_firewalld_enabled
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include enable_firewalld
class enable_firewalld {
service {'firewalld':
enable => true,
ensure => 'running',
}
}
|
The system includes support for Internet Protocol
version 6. A major and often-mentioned improvement over IPv4 is its
enormous increase in the number of available addresses. Another
important feature is its support for automatic configuration of
many network settings. |
contains 6 rules |
Configure IPv6 Settings if Necessary
[ref]groupA major feature of IPv6 is the extent to which systems
implementing it can automatically configure their networking
devices using information from the network. From a security
perspective, manually configuring important configuration
information is preferable to accepting it from the network
in an unauthenticated fashion. |
contains 6 rules |
Disable Accepting ICMP Redirects for All IPv6 Interfaces
[ref]ruleTo set the runtime status of the net.ipv6.conf.all.accept_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.all.accept_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.all.accept_redirects = 0 Rationale:An illicit ICMP redirect message could result in a man-in-the-middle attack. Identifiers:
CCE-85708-6 References:
BP28(R22), 3.3.2, 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.1.20, CCI-000366, CCI-001551, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), CM-6(b), CM-6.1(iv), PR.IP-1, PR.PT-3, SRG-OS-000480-GPOS-00227, SLES-15-040341, SV-235020r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: XCCDF Value sysctl_net_ipv6_conf_all_accept_redirects_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_all_accept_redirects_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv6.conf.all.accept_redirects is set
sysctl:
name: net.ipv6.conf.all.accept_redirects
value: '{{ sysctl_net_ipv6_conf_all_accept_redirects_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85708-6
- DISA-STIG-SLES-15-040341
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_all_accept_redirects
|
Disable Kernel Parameter for Accepting Source-Routed Packets on all IPv6 Interfaces
[ref]ruleTo set the runtime status of the net.ipv6.conf.all.accept_source_route kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.all.accept_source_route=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.all.accept_source_route = 0 Rationale:Source-routed packets allow the source of the packet to suggest routers
forward the packet along a different path than configured on the router, which can
be used to bypass network security measures. This requirement applies only to the
forwarding of source-routerd traffic, such as when IPv6 forwarding is enabled and
the system is functioning as a router.
Accepting source-routed packets in the IPv6 protocol has few legitimate
uses. It should be disabled unless it is absolutely required. Identifiers:
CCE-85649-2 References:
BP28(R22), 3.3.1, 1, 12, 13, 14, 15, 16, 18, 4, 6, 8, 9, APO01.06, APO13.01, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.07, DSS06.02, 3.1.20, CCI-000366, 4.2.3.4, 4.3.3.4, 4.4.3.3, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), CM-6(a), DE.AE-1, ID.AM-3, PR.AC-5, PR.DS-5, PR.PT-4, SRG-OS-000480-GPOS-00227, SLES-15-040310, SV-235015r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: XCCDF Value sysctl_net_ipv6_conf_all_accept_source_route_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_all_accept_source_route_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv6.conf.all.accept_source_route is set
sysctl:
name: net.ipv6.conf.all.accept_source_route
value: '{{ sysctl_net_ipv6_conf_all_accept_source_route_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85649-2
- DISA-STIG-SLES-15-040310
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_all_accept_source_route
|
Disable Kernel Parameter for IPv6 Forwarding
[ref]ruleTo set the runtime status of the net.ipv6.conf.all.forwarding kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.all.forwarding=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.all.forwarding = 0 Rationale:IP forwarding permits the kernel to forward packets from one network
interface to another. The ability to forward packets between two networks is
only appropriate for systems acting as routers. Identifiers:
CCE-85713-6 References:
3.2.1, 1, 11, 12, 13, 14, 15, 16, 2, 3, 7, 8, 9, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS05.02, DSS05.05, DSS05.07, DSS06.06, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), CM-6(b), CM-6.1(iv), DE.CM-1, PR.DS-4, PR.IP-1, PR.PT-3, SRG-OS-000480-GPOS-00227, SLES-15-040381, SV-235025r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: XCCDF Value sysctl_net_ipv6_conf_all_forwarding_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_all_forwarding_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv6.conf.all.forwarding is set
sysctl:
name: net.ipv6.conf.all.forwarding
value: '{{ sysctl_net_ipv6_conf_all_forwarding_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85713-6
- DISA-STIG-SLES-15-040381
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_all_forwarding
|
Disable Kernel Parameter for Accepting ICMP Redirects by Default on IPv6 Interfaces
[ref]ruleTo set the runtime status of the net.ipv6.conf.default.accept_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.default.accept_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.default.accept_redirects = 0 Rationale:An illicit ICMP redirect message could result in a man-in-the-middle attack. Identifiers:
CCE-85722-7 References:
BP28(R22), 3.3.2, 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.1.20, CCI-000366, CCI-001551, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-6(b), CM-6.1(iv), PR.IP-1, PR.PT-3, SRG-OS-000480-GPOS-00227, SLES-15-040350, SV-235021r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: XCCDF Value sysctl_net_ipv6_conf_default_accept_redirects_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_default_accept_redirects_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv6.conf.default.accept_redirects is set
sysctl:
name: net.ipv6.conf.default.accept_redirects
value: '{{ sysctl_net_ipv6_conf_default_accept_redirects_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85722-7
- DISA-STIG-SLES-15-040350
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_default_accept_redirects
|
Disable Kernel Parameter for Accepting Source-Routed Packets on IPv6 Interfaces by Default
[ref]ruleTo set the runtime status of the net.ipv6.conf.default.accept_source_route kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.default.accept_source_route=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.default.accept_source_route = 0 Rationale:Source-routed packets allow the source of the packet to suggest routers
forward the packet along a different path than configured on the router, which can
be used to bypass network security measures. This requirement applies only to the
forwarding of source-routerd traffic, such as when IPv6 forwarding is enabled and
the system is functioning as a router.
Accepting source-routed packets in the IPv6 protocol has few legitimate
uses. It should be disabled unless it is absolutely required. Identifiers:
CCE-85653-4 References:
BP28(R22), 3.3.1, 1, 12, 13, 14, 15, 16, 18, 4, 6, 8, 9, APO01.06, APO13.01, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.07, DSS06.02, 3.1.20, CCI-000366, 4.2.3.4, 4.3.3.4, 4.4.3.3, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), CM-6(a), CM-6(b), CM-6.1(iv), DE.AE-1, ID.AM-3, PR.AC-5, PR.DS-5, PR.PT-4, SRG-OS-000480-GPOS-00227, SLES-15-040321, SV-235017r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: XCCDF Value sysctl_net_ipv6_conf_default_accept_source_route_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_default_accept_source_route_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv6.conf.default.accept_source_route is set
sysctl:
name: net.ipv6.conf.default.accept_source_route
value: '{{ sysctl_net_ipv6_conf_default_accept_source_route_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85653-4
- DISA-STIG-SLES-15-040321
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_default_accept_source_route
|
Disable Kernel Parameter for IPv6 Forwarding by default
[ref]ruleTo set the runtime status of the net.ipv6.conf.default.forwarding kernel parameter, run the following command: $ sudo sysctl -w net.ipv6.conf.default.forwarding=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv6.conf.default.forwarding = 0 Rationale:IP forwarding permits the kernel to forward packets from one network
interface to another. The ability to forward packets between two networks is
only appropriate for systems acting as routers. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: XCCDF Value sysctl_net_ipv6_conf_default_forwarding_value # promote to variable
set_fact:
sysctl_net_ipv6_conf_default_forwarding_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv6.conf.default.forwarding is set
sysctl:
name: net.ipv6.conf.default.forwarding
value: '{{ sysctl_net_ipv6_conf_default_forwarding_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85725-0
- DISA-STIG-SLES-15-040382
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv6_conf_default_forwarding
|
Kernel Parameters Which Affect Networking
[ref]groupThe sysctl utility is used to set
parameters which affect the operation of the Linux kernel. Kernel parameters
which affect networking and have security implications are described here. |
contains 8 rules |
Network Related Kernel Runtime Parameters for Hosts and Routers
[ref]groupCertain kernel parameters should be set for systems which are
acting as either hosts or routers to improve the system's ability defend
against certain types of IPv4 protocol attacks. |
contains 5 rules |
Disable Accepting ICMP Redirects for All IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.conf.all.accept_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.all.accept_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.all.accept_redirects = 0 Rationale:ICMP redirect messages are used by routers to inform hosts that a more
direct route exists for a particular destination. These messages modify the
host's route table and are unauthenticated. An illicit ICMP redirect
message could result in a man-in-the-middle attack.
This feature of the IPv4 protocol has few legitimate uses. It should be
disabled unless absolutely required." Identifiers:
CCE-85651-8 References:
BP28(R22), 3.3.2, 1, 11, 12, 13, 14, 15, 16, 2, 3, 7, 8, 9, 5.10.1.1, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS05.02, DSS05.05, DSS05.07, DSS06.06, 3.1.20, CCI-000366, CCI-001503, CCI-001551, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), SC-7(a), DE.CM-1, PR.DS-4, PR.IP-1, PR.PT-3, SRG-OS-000480-GPOS-00227, SLES-15-040330, SV-235018r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: XCCDF Value sysctl_net_ipv4_conf_all_accept_redirects_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_all_accept_redirects_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv4.conf.all.accept_redirects is set
sysctl:
name: net.ipv4.conf.all.accept_redirects
value: '{{ sysctl_net_ipv4_conf_all_accept_redirects_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85651-8
- CJIS-5.10.1.1
- DISA-STIG-SLES-15-040330
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_accept_redirects
|
Disable Kernel Parameter for Accepting Source-Routed Packets on all IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.conf.all.accept_source_route kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.all.accept_source_route=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.all.accept_source_route = 0 Rationale:Source-routed packets allow the source of the packet to suggest routers
forward the packet along a different path than configured on the router,
which can be used to bypass network security measures. This requirement
applies only to the forwarding of source-routerd traffic, such as when IPv4
forwarding is enabled and the system is functioning as a router.
Accepting source-routed packets in the IPv4 protocol has few legitimate
uses. It should be disabled unless it is absolutely required. Identifiers:
CCE-85648-4 References:
BP28(R22), 3.3.1, 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-000366, 4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, CM-6(a), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227, SLES-15-040300, SV-235014r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: XCCDF Value sysctl_net_ipv4_conf_all_accept_source_route_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_all_accept_source_route_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv4.conf.all.accept_source_route is set
sysctl:
name: net.ipv4.conf.all.accept_source_route
value: '{{ sysctl_net_ipv4_conf_all_accept_source_route_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85648-4
- DISA-STIG-SLES-15-040300
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_accept_source_route
|
Disable Kernel Parameter for Accepting ICMP Redirects by Default on IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.conf.default.accept_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.default.accept_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.default.accept_redirects = 0 Rationale:ICMP redirect messages are used by routers to inform hosts that a more
direct route exists for a particular destination. These messages modify the
host's route table and are unauthenticated. An illicit ICMP redirect
message could result in a man-in-the-middle attack.
This feature of the IPv4 protocol has few legitimate uses. It should
be disabled unless absolutely required. Identifiers:
CCE-85652-6 References:
BP28(R22), 3.3.3, 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, 5.10.1.1, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-000366, CCI-001551, 4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), CM-6(a), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227, SLES-15-040340, SV-235019r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: XCCDF Value sysctl_net_ipv4_conf_default_accept_redirects_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_default_accept_redirects_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv4.conf.default.accept_redirects is set
sysctl:
name: net.ipv4.conf.default.accept_redirects
value: '{{ sysctl_net_ipv4_conf_default_accept_redirects_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85652-6
- CJIS-5.10.1.1
- DISA-STIG-SLES-15-040340
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_accept_redirects
|
Disable Kernel Parameter for Accepting Source-Routed Packets on IPv4 Interfaces by Default
[ref]ruleTo set the runtime status of the net.ipv4.conf.default.accept_source_route kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.default.accept_source_route=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.default.accept_source_route = 0 Rationale:Source-routed packets allow the source of the packet to suggest routers
forward the packet along a different path than configured on the router,
which can be used to bypass network security measures.
Accepting source-routed packets in the IPv4 protocol has few legitimate
uses. It should be disabled unless it is absolutely required, such as when
IPv4 forwarding is enabled and the system is legitimately functioning as a
router. Identifiers:
CCE-85650-0 References:
BP28(R22), 3.3.1, 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, 5.10.1.1, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-000366, CCI-001551, 4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227, SLES-15-040320, SV-235016r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: XCCDF Value sysctl_net_ipv4_conf_default_accept_source_route_value # promote to variable
set_fact:
sysctl_net_ipv4_conf_default_accept_source_route_value: !!str 0
tags:
- always
- name: Ensure sysctl net.ipv4.conf.default.accept_source_route is set
sysctl:
name: net.ipv4.conf.default.accept_source_route
value: '{{ sysctl_net_ipv4_conf_default_accept_source_route_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85650-0
- CJIS-5.10.1.1
- DISA-STIG-SLES-15-040320
- NIST-800-171-3.1.20
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_accept_source_route
|
Enable Kernel Parameter to Use TCP Syncookies on IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.tcp_syncookies kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.tcp_syncookies=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.tcp_syncookies = 1 Rationale:A TCP SYN flood attack can cause a denial of service by filling a
system's TCP connection table with connections in the SYN_RCVD state.
Syncookies can be used to track a connection when a subsequent ACK is received,
verifying the initiator is attempting a valid connection and is not a flood
source. This feature is activated when a flood condition is detected, and
enables the system to continue servicing valid connection requests. Identifiers:
CCE-83283-2 References:
BP28(R22), 3.3.8, 1, 12, 13, 14, 15, 16, 18, 2, 4, 6, 7, 8, 9, 5.10.1.1, APO01.06, APO13.01, BAI04.04, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.07, DSS06.02, 3.1.20, CCI-000366, CCI-001095, 4.2.3.4, 4.3.3.4, 4.4.3.3, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), SC-5(1), SC-5(2), SC-5(3)(a), CM-6(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.PT-4, SRG-OS-000480-GPOS-00227, SRG-OS-000420-GPOS-00186, SRG-OS-000142-GPOS-00071, SLES-15-010310, SV-234829r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: XCCDF Value sysctl_net_ipv4_tcp_syncookies_value # promote to variable
set_fact:
sysctl_net_ipv4_tcp_syncookies_value: !!str 1
tags:
- always
- name: Ensure sysctl net.ipv4.tcp_syncookies is set
sysctl:
name: net.ipv4.tcp_syncookies
value: '{{ sysctl_net_ipv4_tcp_syncookies_value }}'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83283-2
- CJIS-5.10.1.1
- DISA-STIG-SLES-15-010310
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5(1)
- NIST-800-53-SC-5(2)
- NIST-800-53-SC-5(3)(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_tcp_syncookies
|
Network Parameters for Hosts Only
[ref]groupIf the system is not going to be used as a router, then setting certain
kernel parameters ensure that the host will not perform routing
of network traffic. |
contains 3 rules |
Disable Kernel Parameter for Sending ICMP Redirects on all IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.conf.all.send_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.all.send_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.all.send_redirects = 0 Rationale:ICMP redirect messages are used by routers to inform hosts that a more
direct route exists for a particular destination. These messages contain information
from the system's route table possibly revealing portions of the network topology.
The ability to send ICMP redirects is only appropriate for systems acting as routers. Identifiers:
CCE-85655-9 References:
BP28(R22), 3.2.2, 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, 5.10.1.1, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-000366, 4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, CM-6(a), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227, SLES-15-040370, SV-235023r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: Ensure sysctl net.ipv4.conf.all.send_redirects is set to 0
sysctl:
name: net.ipv4.conf.all.send_redirects
value: '0'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85655-9
- CJIS-5.10.1.1
- DISA-STIG-SLES-15-040370
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_all_send_redirects
|
Disable Kernel Parameter for Sending ICMP Redirects on all IPv4 Interfaces by Default
[ref]ruleTo set the runtime status of the net.ipv4.conf.default.send_redirects kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.conf.default.send_redirects=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.conf.default.send_redirects = 0 Rationale:ICMP redirect messages are used by routers to inform hosts that a more
direct route exists for a particular destination. These messages contain information
from the system's route table possibly revealing portions of the network topology.
The ability to send ICMP redirects is only appropriate for systems acting as routers. Identifiers:
CCE-85654-2 References:
BP28(R22), 3.2.2, 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, 5.10.1.1, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-000366, 4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, CM-6(a), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227, SLES-15-040360, SV-235022r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: Ensure sysctl net.ipv4.conf.default.send_redirects is set to 0
sysctl:
name: net.ipv4.conf.default.send_redirects
value: '0'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85654-2
- CJIS-5.10.1.1
- DISA-STIG-SLES-15-040360
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-SC-5
- NIST-800-53-SC-7(a)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_conf_default_send_redirects
|
Disable Kernel Parameter for IP Forwarding on IPv4 Interfaces
[ref]ruleTo set the runtime status of the net.ipv4.ip_forward kernel parameter, run the following command: $ sudo sysctl -w net.ipv4.ip_forward=0
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : net.ipv4.ip_forward = 0 Warning:
Certain technologies such as virtual machines, containers, etc. rely on IPv4 forwarding to enable and use networking.
Disabling IPv4 forwarding would cause those technologies to stop working. Therefore, this rule should not be used in
profiles or benchmarks that target usage of IPv4 forwarding. Rationale:Routing protocol daemons are typically used on routers to exchange
network topology information with other routers. If this capability is used when
not required, system network information may be unnecessarily transmitted across
the network. Identifiers:
CCE-85709-4 References:
BP28(R22), 3.2.1, 1, 11, 12, 13, 14, 15, 16, 2, 3, 7, 8, 9, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS05.02, DSS05.05, DSS05.07, DSS06.06, 3.1.20, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.9.1.2, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-6(b), CM-6.1(iv), DE.CM-1, PR.DS-4, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227, SLES-15-040380, SV-235024r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: Ensure sysctl net.ipv4.ip_forward is set to 0
sysctl:
name: net.ipv4.ip_forward
value: '0'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85709-4
- DISA-STIG-SLES-15-040380
- NIST-800-171-3.1.20
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_net_ipv4_ip_forward
|
Wireless Networking
[ref]groupWireless networking, such as 802.11
(WiFi) and Bluetooth, can present a security risk to sensitive or
classified systems and networks. Wireless networking hardware is
much more likely to be included in laptop or portable systems than
in desktops or servers.
Removal of hardware provides the greatest assurance that the wireless
capability remains disabled. Acquisition policies often include provisions to
prevent the purchase of equipment that will be used in sensitive spaces and
includes wireless capabilities. If it is impractical to remove the wireless
hardware, and policy permits the device to enter sensitive spaces as long
as wireless is disabled, efforts should instead focus on disabling wireless capability
via software. |
contains 1 rule |
Disable Wireless Through Software Configuration
[ref]groupIf it is impossible to remove the wireless hardware
from the device in question, disable as much of it as possible
through software. The following methods can disable software
support for wireless networking, but note that these methods do not
prevent malicious software or careless users from re-activating the
devices. |
contains 1 rule |
Deactivate Wireless Network Interfaces
[ref]ruleDeactivating wireless network interfaces should prevent
normal usage of the wireless capability.
Configure the system to disable wireless network interfaces by issuing the
following command for every active <WIFI-INTERFACE> in the
system:
$ sudo wicked ifdown <WIFI-INTERFACE>
Also remove the configuration files for every wifi adapter from
/etc/wicked/ifconfig/<WIFI-INTERFACE>.xml to prevent future
connections.Rationale:The use of wireless networking can introduce many different attack vectors into
the organization's network. Common attack vectors such as malicious association
and ad hoc networks will allow an attacker to spoof a wireless access point
(AP), allowing validated systems to connect to the malicious AP and enabling the
attacker to monitor and record network traffic. These malicious APs can also
serve to create a man-in-the-middle attack or be used to create a denial of
service to valid network resources. Identifiers:
CCE-83286-5 References:
3.1.2, 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, 3.1.16, CCI-000085, CCI-002418, CCI-002421, CCI-001444, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, 1315, 1319, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, AC-18(a), AC-18(3), CM-7(a), CM-7(b), CM-6(a), MP-7, PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000299-GPOS-00117, SRG-OS-000300-GPOS-00118, SRG-OS-000424-GPOS-00188, SRG-OS-000481-GPOS-000481, SLES-15-010380, SV-234847r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
nmcli radio wifi off
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
- name: Deactivate Wireless Network Interfaces
command: nmcli radio wifi off
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83286-5
- DISA-STIG-SLES-15-010380
- NIST-800-171-3.1.16
- NIST-800-53-AC-18(3)
- NIST-800-53-AC-18(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- unknown_strategy
- wireless_disable_interfaces
|
Ensure System is Not Acting as a Network Sniffer
[ref]ruleThe system should not be acting as a network sniffer, which can
capture all traffic on the network to which it is connected. Run the following
to determine if any interface is running in promiscuous mode:
$ ip link | grep PROMISC
Promiscuous mode of an interface can be disabled with the following command:
$ sudo ip link set dev device_name multicast off promisc off Rationale:Network interfaces in promiscuous mode allow for the capture of all network traffic
visible to the system. If unauthorized individuals can access these applications, it
may allow them to collect information such as logon IDs, passwords, and key exchanges
between systems.
If the system is being used to perform a network troubleshooting function, the use of these
tools must be documented with the Information Systems Security Manager (ISSM) and restricted
to only authorized personnel. Identifiers:
CCE-85656-7 References:
1, 11, 14, 3, 9, APO11.06, APO12.06, BAI03.10, BAI09.01, BAI09.02, BAI09.03, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.05, DSS04.05, DSS05.02, DSS05.05, DSS06.06, CCI-000366, 4.2.3.4, 4.3.3.3.7, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, SR 7.8, A.11.1.2, A.11.2.4, A.11.2.5, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.16.1.6, A.8.1.1, A.8.1.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), CM-7(2), MA-3, DE.DP-5, ID.AM-1, PR.IP-1, PR.MA-1, PR.PT-3, SRG-OS-000480-GPOS-00227, SLES-15-040390, SV-235027r622137_rule |
File Permissions and Masks
[ref]groupTraditional Unix security relies heavily on file and
directory permissions to prevent unauthorized users from reading or
modifying files to which they should not have access.
Several of the commands in this section search filesystems
for files or directories with certain characteristics, and are
intended to be run on every local partition on a given system.
When the variable PART appears in one of the commands below,
it means that the command is intended to be run repeatedly, with the
name of each local partition substituted for PART in turn.
The following command prints a list of all xfs partitions on the local
system, which is the default filesystem for SUSE Linux Enterprise 15
installations:
$ mount -t xfs | awk '{print $3}'
For any systems that use a different
local filesystem type, modify this command as appropriate. |
contains 27 rules |
Verify Permissions on Important Files and
Directories
[ref]groupPermissions for many files on a system must be set
restrictively to ensure sensitive information is properly protected.
This section discusses important
permission restrictions which can be verified
to ensure that no harmful discrepancies have
arisen. |
contains 18 rules |
Verify Permissions on Files with Local Account Information and Credentials
[ref]groupThe default restrictive permissions for files which act as
important security databases such as passwd , shadow ,
group , and gshadow files must be maintained. Many utilities
need read access to the passwd file in order to function properly, but
read access to the shadow file allows malicious attacks against system
passwords, and should never be enabled. |
contains 1 rule |
Verify Permissions and Ownership of Old Passwords File
[ref]rule To properly set the owner of /etc/security/opasswd , run the command: $ sudo chown root /etc/security/opasswd
To properly set the group owner of /etc/security/opasswd , run the command: $ sudo chgrp root /etc/security/opasswd
To properly set the permissions of /etc/security/opasswd , run the command: $ sudo chmod 0600 /etc/security/opasswd Rationale:The /etc/security/opasswd file stores old passwords to prevent
password reuse. Protection of this file is critical for system security. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Ensure /etc/security/opasswd exist and has the correct permissions
file:
path: /etc/security/opasswd
owner: root
group: root
mode: 384
state: touch
tags:
- CCE-85572-6
- DISA-STIG-SLES-15-020240
- file_etc_security_opasswd
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Verify File Permissions Within Some Important Directories
[ref]groupSome directories contain files whose confidentiality or integrity
is notably important and may also be susceptible to misconfiguration over time, particularly if
unpackaged software is installed. As such,
an argument exists to verify that files' permissions within these directories remain
configured correctly and restrictively. |
contains 10 rules |
Verify that Shared Library Directories Have Root Group Ownership
[ref]ruleSystem-wide shared library files, which are linked to executables
during process load time or run time, are stored in the following directories
by default:
/lib
/lib64
/usr/lib
/usr/lib64
Kernel modules, which can be added to the kernel during runtime, are also
stored in /lib/modules . All files in these directories should be
group-owned by the root user. If the directories, is found to be owned
by a user other than root correct its
ownership with the following command:
$ sudo chgrp root DIR Rationale:Files from shared library directories are loaded into the address
space of processes (including privileged ones) or of the kernel itself at
runtime. Proper ownership of library directories is necessary to protect
the integrity of the system. Remediation Shell script: (show)
find /lib \
/lib64 \
/usr/lib \
/usr/lib64 \
\! -group root -type d -exec chgrp root '{}' \;
Remediation Ansible snippet: (show)
Complexity: | medium |
---|
Disruption: | medium |
---|
Strategy: | restrict |
---|
- name: Read list libraries without root ownership
find:
paths:
- /usr/lib
- /usr/lib64
- /lib
- /lib64
file_type: directory
register: library_dirs_not_group_owned_by_root
tags:
- CCE-85737-5
- DISA-STIG-SLES-15-010356
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- dir_group_ownership_library_dirs
- medium_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set group ownership of system library dirs to root
file:
path: '{{ item.path }}'
group: root
state: directory
mode: '{{ item.mode }}'
with_items: '{{ library_dirs_not_group_owned_by_root.files }}'
when:
- library_dirs_not_group_owned_by_root.matched > 0
- item.gid != 0
tags:
- CCE-85737-5
- DISA-STIG-SLES-15-010356
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- dir_group_ownership_library_dirs
- medium_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Verify that Shared Library Directories Have Root Ownership
[ref]ruleSystem-wide shared library files, which are linked to executables
during process load time or run time, are stored in the following directories
by default:
/lib
/lib64
/usr/lib
/usr/lib64
Kernel modules, which can be added to the kernel during runtime, are also
stored in /lib/modules . All files in these directories should be
owned by the root user. If the directories, is found to be owned
by a user other than root correct its
ownership with the following command:
$ sudo chown root DIR Rationale:Files from shared library directories are loaded into the address
space of processes (including privileged ones) or of the kernel itself at
runtime. Proper ownership of library directories is necessary to protect
the integrity of the system. Remediation Ansible snippet: (show)
Complexity: | medium |
---|
Disruption: | medium |
---|
Strategy: | restrict |
---|
- name: Read list libraries without root ownership
find:
paths:
- /usr/lib
- /usr/lib64
- /lib
- /lib64
file_type: directory
register: library_dirs_not_owned_by_root
tags:
- CCE-85735-9
- DISA-STIG-SLES-15-010354
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- dir_ownership_library_dirs
- medium_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set ownership of system library dirs to root
file:
path: '{{ item.path }}'
owner: root
state: directory
mode: '{{ item.mode }}'
with_items: '{{ library_dirs_not_owned_by_root.files }}'
when: library_dirs_not_owned_by_root.matched > 0
tags:
- CCE-85735-9
- DISA-STIG-SLES-15-010354
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- dir_ownership_library_dirs
- medium_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Verify that Shared Library Directories Have Restrictive Permissions
[ref]ruleSystem-wide shared library directories, which contain are linked to executables
during process load time or run time, are stored in the following directories
by default:
/lib
/lib64
/usr/lib
/usr/lib64
Kernel modules, which can be added to the kernel during runtime, are
stored in /lib/modules . All sub-directories in these directories
should not be group-writable or world-writable. If any file in these
directories is found to be group-writable or world-writable, correct
its permission with the following command:
$ sudo chmod go-w DIR Rationale:If the operating system were to allow any user to make changes to software libraries,
then those changes might be implemented without undergoing the appropriate testing
and approvals that are part of a robust change management process.
This requirement applies to operating systems with software libraries that are accessible
and configurable, as in the case of interpreted languages. Software libraries also include
privileged programs which execute with escalated privileges. Only qualified and authorized
individuals must be allowed to obtain access to information system components for purposes
of initiating changes, including upgrades and modifications. Remediation Shell script: (show)
DIRS="/lib /lib64 /usr/lib /usr/lib64"
for dirPath in $DIRS; do
find "$dirPath" -perm /022 -type d -exec chmod go-w '{}' \;
done
Remediation Ansible snippet: (show)
Complexity: | high |
---|
Disruption: | medium |
---|
Strategy: | restrict |
---|
- name: Read list of world and group writable subdirectories in libraries directories
command: find /lib /lib64 /usr/lib /usr/lib64 -perm /022 -type d
register: world_writable_library_dirs
changed_when: false
failed_when: false
check_mode: false
tags:
- CCE-85753-2
- DISA-STIG-SLES-15-010352
- NIST-800-53-CM-5
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- dir_permissions_library_dirs
- high_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Disable world/group writability to library files
file:
path: '{{ item }}'
mode: go-w
with_items: '{{ world_writable_library_dirs.stdout_lines }}'
when: world_writable_library_dirs.stdout_lines | length > 0
tags:
- CCE-85753-2
- DISA-STIG-SLES-15-010352
- NIST-800-53-CM-5
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- dir_permissions_library_dirs
- high_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Verify that system commands files are group owned by root
[ref]ruleSystem commands files are stored in the following directories by default:
/bin
/sbin
/usr/bin
/usr/sbin
/usr/local/bin
/usr/local/sbin
All files in these directories should be owned by the root group.
If the directory, or any file in these directories, is found to be owned
by a group other than root correct its ownership with the following command:
$ sudo chgrp root FILE Rationale:If the operating system allows any user to make changes to software
libraries, then those changes might be implemented without undergoing the
appropriate testing and approvals that are part of a robust change management
process.
This requirement applies to operating systems with software libraries
that are accessible and configurable, as in the case of interpreted languages.
Software libraries also include privileged programs which execute with
escalated privileges. Only qualified and authorized individuals must be
allowed to obtain access to information system components for purposes
of initiating changes, including upgrades and modifications. Remediation Shell script: (show)
for SYSCMDFILES in /bin /sbin /usr/bin /usr/sbin /usr/local/bin /usr/local/sbin
do
find -L $SYSCMDFILES \! -group root -type f -exec chgrp root '{}' \;
done
Remediation Ansible snippet: (show)
Complexity: | medium |
---|
Disruption: | medium |
---|
Strategy: | restrict |
---|
- name: Retrieve the system command files and set their group ownership to root
command: find -L {{ item }} ! -group root -type f -exec chgrp root '{}' \;
with_items:
- /bin
- /sbin
- /usr/bin
- /usr/sbin
- /usr/local/bin
- /usr/local/sbin
changed_when: false
failed_when: false
check_mode: false
tags:
- CCE-85742-5
- DISA-STIG-SLES-15-010361
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- file_groupownership_system_commands_dirs
- medium_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Verify that System Executables Have Root Ownership
[ref]ruleSystem executables are stored in the following directories by default:
/bin
/sbin
/usr/bin
/usr/libexec
/usr/local/bin
/usr/local/sbin
/usr/sbin
All files in these directories should be owned by the root user.
If any file FILE in these directories is found
to be owned by a user other than root, correct its ownership with the
following command:
$ sudo chown root FILE Rationale:System binaries are executed by privileged users as well as system services,
and restrictive permissions are necessary to ensure that their
execution of these programs cannot be co-opted. Identifiers:
CCE-85730-0 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-001499, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-3 R5.1.1, CIP-003-3 R5.3, CIP-004-3 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-5(6), CM-5(6).1, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000259-GPOS-00100, SLES-15-010359, SV-234842r622137_rule Remediation Shell script: (show)
find /bin/ \
/usr/bin/ \
/usr/local/bin/ \
/sbin/ \
/usr/sbin/ \
/usr/local/sbin/ \
/usr/libexec \
\! -user root -execdir chown root {} \;
Remediation Ansible snippet: (show)
Complexity: | medium |
---|
Disruption: | medium |
---|
Strategy: | restrict |
---|
- name: Read list of system executables without root ownership
command: find /bin/ /usr/bin/ /usr/local/bin/ /sbin/ /usr/sbin/ /usr/local/sbin/
/usr/libexec \! -user root
register: no_root_system_executables
changed_when: false
failed_when: false
check_mode: false
tags:
- CCE-85730-0
- DISA-STIG-SLES-15-010359
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- NIST-800-53-CM-6(a)
- file_ownership_binary_dirs
- medium_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set ownership to root of system executables
file:
path: '{{ item }}'
owner: root
with_items: '{{ no_root_system_executables.stdout_lines }}'
when: no_root_system_executables.stdout_lines | length > 0
tags:
- CCE-85730-0
- DISA-STIG-SLES-15-010359
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- NIST-800-53-CM-6(a)
- file_ownership_binary_dirs
- medium_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Verify that Shared Library Files Have Root Ownership
[ref]ruleSystem-wide shared library files, which are linked to executables
during process load time or run time, are stored in the following directories
by default:
/lib
/lib64
/usr/lib
/usr/lib64
Kernel modules, which can be added to the kernel during runtime, are also
stored in /lib/modules . All files in these directories should be
owned by the root user. If the directory, or any file in these
directories, is found to be owned by a user other than root correct its
ownership with the following command:
$ sudo chown root FILE Rationale:Files from shared library directories are loaded into the address
space of processes (including privileged ones) or of the kernel itself at
runtime. Proper ownership is necessary to protect the integrity of the system. Identifiers:
CCE-85756-5 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-001499, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-3 R5.1.1, CIP-003-3 R5.3, CIP-004-3 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-5(6), CM-5(6).1, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000259-GPOS-00100, SLES-15-010353, SV-234836r622137_rule Remediation Shell script: (show)
for LIBDIR in /usr/lib /usr/lib64 /lib /lib64
do
if [ -d $LIBDIR ]
then
find -L $LIBDIR \! -user root -exec chown root {} \;
fi
done
Remediation Ansible snippet: (show)
Complexity: | medium |
---|
Disruption: | medium |
---|
Strategy: | restrict |
---|
- name: Read list libraries without root ownership
command: find -L /usr/lib /usr/lib64 /lib /lib64 \! -user root
register: libraries_not_owned_by_root
changed_when: false
failed_when: false
check_mode: false
tags:
- CCE-85756-5
- DISA-STIG-SLES-15-010353
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- NIST-800-53-CM-6(a)
- file_ownership_library_dirs
- medium_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set ownership of system libraries to root
file:
path: '{{ item }}'
owner: root
with_items: '{{ libraries_not_owned_by_root.stdout_lines }}'
when: libraries_not_owned_by_root | length > 0
tags:
- CCE-85756-5
- DISA-STIG-SLES-15-010353
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- NIST-800-53-CM-6(a)
- file_ownership_library_dirs
- medium_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Verify that System Executables Have Restrictive Permissions
[ref]ruleSystem executables are stored in the following directories by default:
/bin
/sbin
/usr/bin
/usr/libexec
/usr/local/bin
/usr/local/sbin
/usr/sbin
All files in these directories should not be group-writable or world-writable.
If any file FILE in these directories is found
to be group-writable or world-writable, correct its permission with the
following command:
$ sudo chmod go-w FILE Rationale:System binaries are executed by privileged users, as well as system services,
and restrictive permissions are necessary to ensure execution of these programs
cannot be co-opted. Identifiers:
CCE-85729-2 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-001499, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-3 R5.1.1, CIP-003-3 R5.3, CIP-004-3 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-5(6), CM-5(6).1, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000259-GPOS-00100, SLES-15-010358, SV-234841r622137_rule Remediation Shell script: (show)
DIRS="/bin /usr/bin /usr/local/bin /sbin /usr/sbin /usr/local/sbin /usr/libexec"
for dirPath in $DIRS; do
find "$dirPath" -perm /022 -exec chmod go-w '{}' \;
done
Remediation Ansible snippet: (show)
Complexity: | medium |
---|
Disruption: | medium |
---|
Strategy: | restrict |
---|
- name: Read list of world and group writable system executables
command: find /bin /usr/bin /usr/local/bin /sbin /usr/sbin /usr/local/sbin /usr/libexec
-perm /022 -type f
register: world_writable_library_files
changed_when: false
failed_when: false
check_mode: false
tags:
- CCE-85729-2
- DISA-STIG-SLES-15-010358
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- NIST-800-53-CM-6(a)
- file_permissions_binary_dirs
- medium_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Remove world/group writability of system executables
file:
path: '{{ item }}'
mode: go-w
with_items: '{{ world_writable_library_files.stdout_lines }}'
when: world_writable_library_files.stdout_lines | length > 0
tags:
- CCE-85729-2
- DISA-STIG-SLES-15-010358
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- NIST-800-53-CM-6(a)
- file_permissions_binary_dirs
- medium_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Verify that Shared Library Files Have Restrictive Permissions
[ref]ruleSystem-wide shared library files, which are linked to executables
during process load time or run time, are stored in the following directories
by default:
/lib
/lib64
/usr/lib
/usr/lib64
Kernel modules, which can be added to the kernel during runtime, are
stored in /lib/modules . All files in these directories
should not be group-writable or world-writable. If any file in these
directories is found to be group-writable or world-writable, correct
its permission with the following command:
$ sudo chmod go-w FILE Rationale:Files from shared library directories are loaded into the address
space of processes (including privileged ones) or of the kernel itself at
runtime. Restrictive permissions are necessary to protect the integrity of the system. Identifiers:
CCE-85670-8 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-001499, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-3 R5.1.1, CIP-003-3 R5.3, CIP-004-3 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), CM-5(6), CM-5(6).1, AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000259-GPOS-00100, SLES-15-010351, SV-234834r622137_rule Remediation Shell script: (show)
DIRS="/lib /lib64 /usr/lib /usr/lib64"
for dirPath in $DIRS; do
find "$dirPath" -perm /022 -type f -exec chmod go-w '{}' \;
done
Remediation Ansible snippet: (show)
Complexity: | high |
---|
Disruption: | medium |
---|
Strategy: | restrict |
---|
- name: Read list of world and group writable files in libraries directories
command: find /lib /lib64 /usr/lib /usr/lib64 -perm /022 -type f
register: world_writable_library_files
changed_when: false
failed_when: false
check_mode: false
tags:
- CCE-85670-8
- DISA-STIG-SLES-15-010351
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- NIST-800-53-CM-6(a)
- file_permissions_library_dirs
- high_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Disable world/group writability to library files
file:
path: '{{ item }}'
mode: go-w
with_items: '{{ world_writable_library_files.stdout_lines }}'
when: world_writable_library_files.stdout_lines | length > 0
tags:
- CCE-85670-8
- DISA-STIG-SLES-15-010351
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- NIST-800-53-CM-6(a)
- file_permissions_library_dirs
- high_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Verify that system commands are protected from unauthorized access
[ref]ruleSystem commands are stored in the following directories by default:
/bin
/sbin
/usr/bin
/usr/sbin
/usr/local/bin
/usr/local/sbin
All files in these directories should not be group-writable or world-writable.
If any file FILE in these directories is found
to be group-writable or world-writable, correct its permission with the
following command:
$ sudo chmod 755 FILE Rationale:System binaries are executed by privileged users, as well as system services,
and restrictive permissions are necessary to ensure execution of these programs
cannot be co-opted. Remediation Shell script: (show)
DIRS="/bin /sbin /usr/bin usr/sbin /usr/local/bin /usr/local/sbin"
for dirPath in $DIRS; do
find -L "$dirPath" -perm /022 -type f -exec chmod go-w '{}' \;
done
Remediation Ansible snippet: (show)
Complexity: | medium |
---|
Disruption: | medium |
---|
Strategy: | restrict |
---|
- name: Retrieve the system command files and protect them from unautorized access
command: find -L {{ item }} -perm /022 -type f -exec chmod go-w '{}' \;
with_items:
- /bin
- /sbin
- /usr/bin
- /usr/sbin
- /usr/local/bin
- /usr/local/sbin
changed_when: false
failed_when: false
check_mode: false
tags:
- CCE-85738-3
- DISA-STIG-SLES-15-010357
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- file_permissions_system_commands_dirs
- medium_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Verify the system-wide library files in directories
"/lib", "/lib64", "/usr/lib/" and "/usr/lib64" are owned by root.
[ref]ruleSystem-wide library files are stored in the following directories
by default:
/lib
/lib64
/usr/lib
/usr/lib64
All system-wide shared library files should be protected from unauthorised
access. If any of these files is not owned by root, correct its owner with
the following command:
$ sudo chgrp root FILE Rationale:If the operating system were to allow any user to make changes to software libraries,
then those changes might be implemented without undergoing the appropriate testing and
approvals that are part of a robust change management process.
This requirement applies to operating systems with software libraries that are
accessible and configurable, as in the case of interpreted languages. Software libraries
also include privileged programs which execute with escalated privileges. Only qualified
and authorized individuals must be allowed to obtain access to information system components
for purposes of initiating changes, including upgrades and modifications. Remediation Shell script: (show)
find /lib \
/lib64 \
/usr/lib \
/usr/lib64 \
\! -group root -type f -exec chgrp root '{}' \;
Remediation Ansible snippet: (show)
Complexity: | high |
---|
Disruption: | medium |
---|
Strategy: | restrict |
---|
- name: Read list libraries without root ownership
find:
paths:
- /usr/lib
- /usr/lib64
- /lib
- /lib64
file_type: file
register: library_files_not_group_owned_by_root
tags:
- CCE-85736-7
- DISA-STIG-SLES-15-010355
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- high_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- root_permissions_syslibrary_files
- name: Set group ownership of system library files to root
file:
path: '{{ item.path }}'
group: root
state: file
mode: '{{ item.mode }}'
with_items: '{{ library_files_not_group_owned_by_root.files }}'
when:
- library_files_not_group_owned_by_root.matched > 0
- item.gid != 0
tags:
- CCE-85736-7
- DISA-STIG-SLES-15-010355
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- high_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- root_permissions_syslibrary_files
|
Verify that All World-Writable Directories Have Sticky Bits Set
[ref]ruleWhen the so-called 'sticky bit' is set on a directory,
only the owner of a given file may remove that file from the
directory. Without the sticky bit, any user with write access to a
directory may remove any file in the directory. Setting the sticky
bit prevents users from removing each other's files. In cases where
there is no reason for a directory to be world-writable, a better
solution is to remove that permission rather than to set the sticky
bit. However, if a directory is used by a particular application,
consult that application's documentation instead of blindly
changing modes.
To set the sticky bit on a world-writable directory DIR, run the
following command:
$ sudo chmod +t DIR Rationale:Failing to set the sticky bit on public directories allows unauthorized
users to delete files in the directory structure.
The only authorized public directories are those temporary directories
supplied with the system, or those designed to be temporary file
repositories. The setting is normally reserved for directories used by the
system, by users for temporary file storage (such as /tmp ), and
for directories requiring global read/write access. Identifiers:
CCE-83282-4 References:
BP28(R40), 1.1.22, 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-001090, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-3 R5.1.1, CIP-003-3 R5.3, CIP-004-3 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000138-GPOS-00069, SLES-15-010300, SV-234828r622137_rule Remediation Shell script: (show)
df --local -P | awk '{if (NR!=1) print $6}' \
| xargs -I '{}' find '{}' -xdev -type d \
\( -perm -0002 -a ! -perm -1000 \) 2>/dev/null \
| xargs chmod a+t
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Get all world-writable directories with no sticky bits set
shell: |
set -o pipefail
df --local -P | awk '{if (NR!=1) print $6}' | xargs -I '{}' find '{}' -xdev -type d \( -perm -0002 -a ! -perm -1000 \) 2>/dev/null
register: dir_output
tags:
- CCE-83282-4
- DISA-STIG-SLES-15-010300
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- dir_perms_world_writable_sticky_bits
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: ensure sticky bit is set
file:
path: '{{ item }}'
mode: a+t
with_items:
- '{{ dir_output.stdout_lines }}'
tags:
- CCE-83282-4
- DISA-STIG-SLES-15-010300
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- dir_perms_world_writable_sticky_bits
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure All World-Writable Directories Are Group Owned by a System Account
[ref]ruleAll directories in local partitions which are
world-writable should be group owned by root or another
system account. If any world-writable directories are not
group owned by a system account, this should be investigated.
Following this, the files should be deleted or assigned to an
appropriate group. Rationale:Allowing a user account to group own a world-writable directory is
undesirable because it allows the owner of that directory to remove
or replace any files that may be placed in the directory by other
users. Identifiers:
CCE-85637-7 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-000366, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, SLES-15-040180, SV-235002r622137_rule |
Verify that system commands directories have root as a group owner
[ref]ruleSystem commands are stored in the following directories:
by default:
/bin
/sbin
/usr/bin
/usr/sbin
/usr/local/bin
/usr/local/sbin
All these directories should have root user as a group owner.
If any system command directory is not group owned by a user other than root
correct its ownership with the following command:
$ sudo chgrp root DIR Rationale:If the operating system were to allow any user to make changes to
software libraries, then those changes might be implemented without
undergoing the appropriate testing and approvals that are part of a
robust change management process.
This requirement applies to operating systems with software libraries
that are accessible and configurable, as in the case of interpreted languages.
Software libraries also include privileged programs which execute with escalated
privileges. Only qualified and authorized individuals must be allowed to obtain
access to information system components for purposes of initiating changes,
including upgrades and modifications. Remediation Shell script: (show)
for SYSCMDDIRS in /bin /sbin /usr/bin /usr/sbin /usr/local/bin /usr/local/sbin
do
find -L $SYSCMDDIRS ! -group root -type d -exec chgrp root '{}' \;
done
Remediation Ansible snippet: (show)
Complexity: | medium |
---|
Disruption: | medium |
---|
Strategy: | restrict |
---|
- name: Retrive system commands directories and set its group owner to root
command: find -L {{ item }} ! -group root -type d -exec chgrp root '{}' \;
with_items:
- /bin
- /sbin
- /usr/bin
- /usr/sbin
- /usr/local/bin
- /usr/local/sbin
changed_when: false
failed_when: false
check_mode: false
tags:
- CCE-85743-3
- DISA-STIG-SLES-15-010362
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- dir_system_commands_group_root_owned
- medium_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Verify that system commands directories have root ownership
[ref]ruleSystem commands are stored in the following directories by default:
/bin
/sbin
/usr/bin
/usr/sbin
/usr/local/bin
/usr/local/sbin
All these directories should be owned by the root user.
If any system command directory is not owned by a user other than root
correct its ownership with the following command:
$ sudo chown root DIR Rationale:If the operating system were to allow any user to make changes to
software libraries, then those changes might be implemented without
undergoing the appropriate testing and approvals that are part of a
robust change management process.
This requirement applies to operating systems with software libraries
that are accessible and configurable, as in the case of interpreted languages.
Software libraries also include privileged programs which execute with escalated
privileges. Only qualified and authorized individuals must be allowed to obtain
access to information system components for purposes of initiating changes,
including upgrades and modifications. Remediation Shell script: (show)
#!/bin/bash
for SYSCMDDIRS in /bin /sbin /usr/bin /usr/sbin /usr/local/bin /usr/local/sbin
do
find -L $SYSCMDDIRS \! -user root -type d -exec chown root {} \;
done
Remediation Ansible snippet: (show)
Complexity: | medium |
---|
Disruption: | medium |
---|
Strategy: | restrict |
---|
- name: Set ownership of directories that contain system commands to root
file:
path: '{{ item }}'
owner: root
recurse: 'yes'
state: directory
follow: 'no'
with_items:
- /bin
- /sbin
- /usr/bin
- usr/sbin
- usr/local/bin
- /usr/local/sbin
tags:
- CCE-85741-7
- DISA-STIG-SLES-15-010360
- NIST-800-53-CM-5(6)
- NIST-800-53-CM-5(6).1
- dir_system_commands_root_owned
- medium_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Ensure All Files Are Owned by a Group
[ref]ruleIf any files are not owned by a group, then the
cause of their lack of group-ownership should be investigated.
Following this, the files should be deleted or assigned to an
appropriate group. The following command will discover and print
any files on local partitions which do not belong to a valid group:
$ df --local -P | awk '{if (NR!=1) print $6}' | sudo xargs -I '{}' find '{}' -xdev -nogroup
To search all filesystems on a system including network mounted
filesystems the following command can be run manually for each partition:
$ sudo find PARTITION -xdev -nogroup Warning:
This rule only considers local groups.
If you have your groups defined outside /etc/group , the rule won't consider those. Rationale:Unowned files do not directly imply a security problem, but they are generally
a sign that something is amiss. They may
be caused by an intruder, by incorrect software installation or
draft software removal, or by failure to remove all files belonging
to a deleted account. The files should be repaired so they
will not cause problems when accounts are created in the future,
and the cause should be discovered and addressed. Identifiers:
CCE-85658-3 References:
6.1.10, 1, 11, 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.02, DSS06.03, DSS06.06, DSS06.10, CCI-000366, CCI-002165, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.18.1.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.DS-5, PR.PT-3, SRG-OS-000480-GPOS-00227, SLES-15-040410, SV-235029r622137_rule |
Ensure All Files Are Owned by a User
[ref]ruleIf any files are not owned by a user, then the
cause of their lack of ownership should be investigated.
Following this, the files should be deleted or assigned to an
appropriate user. The following command will discover and print
any files on local partitions which do not belong to a valid user:
$ df --local -P | awk {'if (NR!=1) print $6'} | sudo xargs -I '{}' find '{}' -xdev -nouser
To search all filesystems on a system including network mounted
filesystems the following command can be run manually for each partition:
$ sudo find PARTITION -xdev -nouser Warning:
For this rule to evaluate centralized user accounts, getent must be working properly
so that running the command getent passwd returns a list of all users in your organization.
If using the System Security Services Daemon (SSSD), enumerate = true must be configured
in your organization's domain to return a complete list of users Warning:
Enabling this rule will result in slower scan times depending on the size of your organization
and number of centralized users. Rationale:Unowned files do not directly imply a security problem, but they are generally
a sign that something is amiss. They may
be caused by an intruder, by incorrect software installation or
draft software removal, or by failure to remove all files belonging
to a deleted account. The files should be repaired so they
will not cause problems when accounts are created in the future,
and the cause should be discovered and addressed. Identifiers:
CCE-85657-5 References:
6.1.9, 11, 12, 13, 14, 15, 16, 18, 3, 5, 9, APO01.06, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, CCI-000366, CCI-002165, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 5.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.AC-6, PR.DS-5, PR.IP-1, PR.PT-3, SRG-OS-000480-GPOS-00227, SLES-15-040400, SV-235028r622137_rule |
Verify permissions of log files
[ref]ruleAny operating system providing too much information in error messages
risks compromising the data and security of the structure, and content
of error messages needs to be carefully considered by the organization.
Organizations carefully consider the structure/content of error messages.
The extent to which information systems are able to identify and handle
error conditions is guided by organizational policy and operational
requirements. Information that could be exploited by adversaries includes,
for example, erroneous logon attempts with passwords entered by mistake
as the username, mission/business information that can be derived from
(if not stated explicitly by) information recorded, and personal
information, such as account numbers, social security numbers, and credit
card numbers. Rationale:The SUSE Linux Enterprise 15 must generate error messages that provide information
necessary for corrective actions without revealing information that could
be exploited by adversaries. Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | configure |
---|
- name: Find log files
find:
paths: /var/log/
recurse: true
patterns: '*'
register: log_files
tags:
- CCE-85755-7
- DISA-STIG-SLES-15-010340
- NIST-800-53-SI-11(a)
- NIST-800-53-SI-11(b)
- NIST-800-53-SI-11.1(iii)
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- permissions_local_var_log
- name: Configure permission for /var/log/
lineinfile:
path: /etc/permissions.local
regexp: ^{{ item.path }}\s+\w+\:\w+\d+\s*$
line: "{{ item.path }}\t\t\t\t{{ item.pw_name }}:{{ item.gr_name }}\t640"
state: present
when: (item.mode | int) > 640
with_items: '{{ log_files.files }}'
register: update_permissions_local_logs_result
tags:
- CCE-85755-7
- DISA-STIG-SLES-15-010340
- NIST-800-53-SI-11(a)
- NIST-800-53-SI-11(b)
- NIST-800-53-SI-11.1(iii)
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- permissions_local_var_log
- name: Correct file permissions for /var/log
shell: |
chkstat --set --system
when: update_permissions_local_logs_result.changed
tags:
- CCE-85755-7
- DISA-STIG-SLES-15-010340
- NIST-800-53-SI-11(a)
- NIST-800-53-SI-11(b)
- NIST-800-53-SI-11.1(iii)
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- permissions_local_var_log
|
Restrict Dynamic Mounting and Unmounting of
Filesystems
[ref]groupLinux includes a number of facilities for the automated addition
and removal of filesystems on a running system. These facilities may be
necessary in many environments, but this capability also carries some risk -- whether direct
risk from allowing users to introduce arbitrary filesystems,
or risk that software flaws in the automated mount facility itself could
allow an attacker to compromise the system.
This command can be used to list the types of filesystems that are
available to the currently executing kernel:
$ find /lib/modules/`uname -r`/kernel/fs -type f -name '*.ko'
If these filesystems are not required then they can be explicitly disabled
in a configuratio file in /etc/modprobe.d . |
contains 2 rules |
Disable the Automounter
[ref]ruleThe autofs daemon mounts and unmounts filesystems, such as user
home directories shared via NFS, on demand. In addition, autofs can be used to handle
removable media, and the default configuration provides the cdrom device as /misc/cd .
However, this method of providing access to removable media is not common, so autofs
can almost always be disabled if NFS is not in use. Even if NFS is required, it may be
possible to configure filesystem mounts statically by editing /etc/fstab
rather than relying on the automounter.
The autofs service can be disabled with the following command:
$ sudo systemctl mask --now autofs.service Rationale:Disabling the automounter permits the administrator to
statically control filesystem mounting through /etc/fstab .
Additionally, automatically mounting filesystems permits easy introduction of
unknown devices, thereby facilitating malicious activity. Identifiers:
CCE-83278-2 References:
1.1.23, 1, 12, 15, 16, 5, APO13.01, DSS01.04, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.4.6, CCI-000366, CCI-000778, CCI-001958, 164.308(a)(3)(i), 164.308(a)(3)(ii)(A), 164.310(d)(1), 164.310(d)(2), 164.312(a)(1), 164.312(a)(2)(iv), 164.312(b), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.6, A.11.2.6, A.13.1.1, A.13.2.1, A.18.1.4, A.6.2.1, A.6.2.2, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, CM-7(a), CM-7(b), CM-6(a), MP-7, PR.AC-1, PR.AC-3, PR.AC-6, PR.AC-7, SRG-OS-000114-GPOS-00059, SRG-OS-000378-GPOS-00163, SRG-OS-000480-GPOS-00227, SLES-15-010240, SV-234823r622137_rule Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'autofs.service'
"$SYSTEMCTL_EXEC" disable 'autofs.service'
"$SYSTEMCTL_EXEC" mask 'autofs.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^autofs.socket'; then
"$SYSTEMCTL_EXEC" stop 'autofs.socket'
"$SYSTEMCTL_EXEC" mask 'autofs.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'autofs.service' || true
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
- name: Disable service autofs
block:
- name: Gather the service facts
service_facts: null
- name: Disable service autofs
systemd:
name: autofs.service
enabled: 'no'
state: stopped
masked: 'yes'
when: '"autofs.service" in ansible_facts.services'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83278-2
- DISA-STIG-SLES-15-010240
- NIST-800-171-3.4.6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_autofs_disabled
- name: Unit Socket Exists - autofs.socket
command: systemctl list-unit-files autofs.socket
args:
warn: false
register: socket_file_exists
changed_when: false
ignore_errors: true
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83278-2
- DISA-STIG-SLES-15-010240
- NIST-800-171-3.4.6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_autofs_disabled
- name: Disable socket autofs
systemd:
name: autofs.socket
enabled: 'no'
state: stopped
masked: 'yes'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"autofs.socket" in socket_file_exists.stdout_lines[1]'
tags:
- CCE-83278-2
- DISA-STIG-SLES-15-010240
- NIST-800-171-3.4.6
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_autofs_disabled
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include disable_autofs
class disable_autofs {
service {'autofs':
enable => false,
ensure => 'stopped',
}
}
|
Disable Modprobe Loading of USB Storage Driver
[ref]ruleTo prevent USB storage devices from being used, configure the kernel module loading system
to prevent automatic loading of the USB storage driver.
To configure the system to prevent the usb-storage
kernel module from being loaded, add the following line to a file in the directory /etc/modprobe.d :
install usb-storage /bin/true
This will prevent the modprobe program from loading the usb-storage
module, but will not prevent an administrator (or another program) from using the
insmod program to load the module manually.Rationale:USB storage devices such as thumb drives can be used to introduce
malicious software. Identifiers:
CCE-83294-9 References:
1.1.3, 1, 12, 15, 16, 5, APO13.01, DSS01.04, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.1.21, CCI-000366, CCI-000778, CCI-001958, 164.308(a)(3)(i), 164.308(a)(3)(ii)(A), 164.310(d)(1), 164.310(d)(2), 164.312(a)(1), 164.312(a)(2)(iv), 164.312(b), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.6, A.11.2.6, A.13.1.1, A.13.2.1, A.18.1.4, A.6.2.1, A.6.2.2, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, CM-7(a), CM-7(b), CM-6(a), MP-7, PR.AC-1, PR.AC-3, PR.AC-6, PR.AC-7, SRG-OS-000114-GPOS-00059, SRG-OS-000378-GPOS-00163, SRG-OS-000480-GPOS-00227, SLES-15-010480, SV-234856r622137_rule Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if ! LC_ALL=C grep -q -m 1 "^blacklist usb-storage$" /etc/modprobe.d/50-blacklist.conf ; then
echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/50-blacklist.conf
echo "blacklist usb-storage" >> /etc/modprobe.d/50-blacklist.conf
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: Ensure kernel module 'usb-storage' is disabled
lineinfile:
create: true
dest: /etc/modprobe.d/50-blacklist.conf
regexp: ^blacklist usb-storage$
line: blacklist usb-storage
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83294-9
- DISA-STIG-SLES-15-010480
- NIST-800-171-3.1.21
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- disable_strategy
- kernel_module_usb-storage_disabled
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
|
Restrict Partition Mount Options
[ref]groupSystem partitions can be mounted with certain options
that limit what files on those partitions can do. These options
are set in the /etc/fstab configuration file, and can be
used to make certain types of malicious behavior more difficult. |
contains 2 rules |
Add nosuid Option to /home
[ref]ruleThe nosuid mount option can be used to prevent
execution of setuid programs in /home . The SUID and SGID permissions
should not be required in these user data directories.
Add the nosuid option to the fourth column of
/etc/fstab for the line which controls mounting of
/home . Rationale:The presence of SUID and SGID executables should be tightly controlled. Users
should not be able to execute SUID or SGID binaries from user home directory partitions. Identifiers:
CCE-85633-6 References:
BP28(R12), 11, 13, 14, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS05.06, DSS06.06, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.11.2.9, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.8.2.1, A.8.2.2, A.8.2.3, A.8.3.1, A.8.3.3, A.9.1.2, CIP-003-3 R5.1.1, CIP-003-3 R5.3, CIP-004-3 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-7(a), CM-7(b), CM-6(a), AC-6, AC-6(1), MP-7, PR.IP-1, PR.PT-2, PR.PT-3, SRG-OS-000368-GPOS-00154, SRG-OS-000480-GPOS-00227, SLES-15-040140, SV-234998r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
function perform_remediation {
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" "/home")"
grep "$mount_point_match_regexp" -q /etc/fstab \
|| { echo "The mount point '/home' is not even in /etc/fstab, so we can't set up mount options" >&2;
echo "Not remediating, because there is no record of /home in /etc/fstab" >&2; return 1; }
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" /home)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if [ "$(grep -c "$mount_point_match_regexp" /etc/fstab)" -eq 0 ]; then
# runtime opts without some automatic kernel/userspace-added defaults
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 | awk '{print $4}' \
| sed -E "s/(rw|defaults|seclabel|nosuid)(,|$)//g;s/,$//")
[ "$previous_mount_opts" ] && previous_mount_opts+=","
echo " /home defaults,${previous_mount_opts}nosuid 0 0" >> /etc/fstab
# If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
elif [ "$(grep "$mount_point_match_regexp" /etc/fstab | grep -c "nosuid")" -eq 0 ]; then
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,nosuid|" /etc/fstab
fi
if mkdir -p "/home"; then
if mountpoint -q "/home"; then
mount -o remount --target "/home"
else
mount --target "/home"
fi
fi
}
perform_remediation
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Strategy: | configure |
---|
- name: Check information associated to mountpoint
command: findmnt --fstab '/home'
register: device_name
failed_when: device_name.rc > 1
changed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85633-6
- DISA-STIG-SLES-15-040140
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_home_nosuid
- no_reboot_needed
- name: Create mount_info dictionary variable
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- '{{ device_name.stdout_lines[0].split() | list | lower }}'
- '{{ device_name.stdout_lines[1].split() | list }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- device_name.stdout is defined and device_name.stdout_lines is defined
- (device_name.stdout | length > 0)
tags:
- CCE-85633-6
- DISA-STIG-SLES-15-040140
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_home_nosuid
- no_reboot_needed
- name: If /home not mounted, craft mount_info manually
set_fact:
mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
with_together:
- - target
- source
- fstype
- options
- - /home
- ''
- ''
- defaults
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- ("--fstab" | length == 0)
- (device_name.stdout | length == 0)
tags:
- CCE-85633-6
- DISA-STIG-SLES-15-040140
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_home_nosuid
- no_reboot_needed
- name: Make sure nosuid option is part of the to /home options
set_fact:
mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',nosuid''
}) }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- mount_info is defined and "nosuid" not in mount_info.options
tags:
- CCE-85633-6
- DISA-STIG-SLES-15-040140
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_home_nosuid
- no_reboot_needed
- name: Ensure /home is mounted with nosuid option
mount:
path: /home
src: '{{ mount_info.source }}'
opts: '{{ mount_info.options }}'
state: mounted
fstype: '{{ mount_info.fstype }}'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- (device_name.stdout is defined and (device_name.stdout | length > 0)) or ("--fstab"
| length == 0)
tags:
- CCE-85633-6
- DISA-STIG-SLES-15-040140
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_home_nosuid
- no_reboot_needed
|
Add nosuid Option to Removable Media Partitions
[ref]ruleThe nosuid mount option prevents set-user-identifier (SUID)
and set-group-identifier (SGID) permissions from taking effect. These permissions
allow users to execute binaries with the same permissions as the owner and group
of the file respectively. Users should not be allowed to introduce SUID and SGID
files into the system via partitions mounted from removeable media.
Add the nosuid option to the fourth column of
/etc/fstab for the line which controls mounting of
any removable media partitions. Rationale:The presence of SUID and SGID executables should be tightly controlled. Allowing
users to introduce SUID or SGID binaries from partitions mounted off of
removable media would allow them to introduce their own highly-privileged programs. Identifiers:
CCE-85634-4 References:
1.1.21, 11, 12, 13, 14, 15, 16, 18, 3, 5, 8, 9, APO01.06, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.06, DSS05.07, DSS06.02, DSS06.03, DSS06.06, CCI-000366, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 5.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.11.2.6, A.11.2.9, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.1, A.8.2.2, A.8.2.3, A.8.3.1, A.8.3.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-3 R5.1.1, CIP-003-3 R5.3, CIP-004-3 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-7(a), CM-7(b), CM-6(a), AC-6, AC-6(1), MP-7, PR.AC-3, PR.AC-4, PR.AC-6, PR.DS-5, PR.IP-1, PR.PT-2, PR.PT-3, SRG-OS-000480-GPOS-00227, SLES-15-040150, SV-234999r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
var_removable_partition="/dev/cdrom"
device_regex="^\s*$var_removable_partition\s\+"
mount_option="nosuid"
if grep -q $device_regex /etc/fstab ; then
previous_opts=$(grep $device_regex /etc/fstab | awk '{print $4}')
sed -i "s|\($device_regex.*$previous_opts\)|\1,$mount_option|" /etc/fstab
else
echo "Not remediating, because there is no record of $var_removable_partition in /etc/fstab" >&2
return 1
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | high |
---|
Strategy: | configure |
---|
- name: XCCDF Value var_removable_partition # promote to variable
set_fact:
var_removable_partition: !!str /dev/cdrom
tags:
- always
- name: Ensure permission nosuid are set on var_removable_partition
lineinfile:
path: /etc/fstab
regexp: ^\s*({{ var_removable_partition }})\s+([^\s]*)\s+([^\s]*)\s+([^\s]*)(.*)$
backrefs: true
line: \1 \2 \3 \4,nosuid \5
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85634-4
- DISA-STIG-SLES-15-040150
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-MP-7
- configure_strategy
- high_disruption
- low_complexity
- medium_severity
- mount_option_nosuid_removable_partitions
- no_reboot_needed
|
Verify Permissions on Important Files and
Directories Are Configured in /etc/permissions.local
[ref]groupPermissions for many files on a system must be set
restrictively to ensure sensitive information is properly protected.
This section discusses the /etc/permissions.local file, where
expected permissions can be configured to be checked and fixed through
usage of the chkstat command. |
contains 3 rules |
Verify that local /var/log/messages is not world-readable
[ref]ruleFiles containing sensitive informations should be protected by restrictive
permissions. Most of the time, there is no need that these files need to be read by any non-root user
To properly set the permissions of /var/log/messages , run the command:
$ sudo chmod 0640 /var/log/messages
Check that "permissions.local" file contains the correct permissions rules with the following command:
# grep -i messages /etc/permissions.local
/var/log/messages root:root 640 Rationale:The /var/log/messages file contains system error messages. Only
authorized personnel should be aware of errors and the details of the
errors. Error messages are an indicator of an organization's operational
state or can identify the SUSE operating system or platform. Additionally,
Personally Identifiable Information (PII) and operational information must
not be revealed through error messages to unauthorized personnel or their
designated representatives. Remediation Shell script: (show)
#!/bin/bash
CORRECT_PERMISSIONS="/var/log/messages root:root 640"
err_cnt=0
message_permissions=$(grep -i messages /etc/permissions.local)
if [ ${#message_permissions} -eq 0 ]
then
echo "There are no permission rules for system errors messages. We will add them"
echo $CORRECT_PERMISSIONS >> /etc/permissions.local
err_cnt=$((err_cnt+1))
fi
check_message_permissions=$(stat -c "%n %U:%G %a" /var/log/messages)
if [ "$check_message_permissions" != "$CORRECT_PERMISSIONS" ]
then
echo "The permissions are not correct"
err_cnt=$((err_cnt+1))
fi
if [ ${#err_cnt} -gt 0 ]
then
echo "Set the permissions"
chkstat --set --system
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | configure |
---|
- name: Configure permission for /var/log/messages
lineinfile:
path: /etc/permissions.local
create: true
regexp: ^\/var\/log\/messages\s+root.*
line: /var/log/messages root:root 640
state: present
register: update_permissions_local_result
tags:
- CCE-83285-7
- DISA-STIG-SLES-15-010350
- configure_strategy
- file_permissions_local_var_log_messages
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Correct file permissions after update /etc/permissions.local
shell: |
set -o pipefail chkstat --set --system
when: update_permissions_local_result.changed
tags:
- CCE-83285-7
- DISA-STIG-SLES-15-010350
- configure_strategy
- file_permissions_local_var_log_messages
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
|
Verify Permissions of Local Logs of audit Tools
[ref]ruleThe SUSE operating system audit tools must have the proper permissions
configured to protect against unauthorized access.
Check that "permissions.local" file contains the correct permissions rules
with the following command:
grep "^/usr/sbin/au" /etc/permissions.local
/usr/sbin/audispd root:root 0750
/usr/sbin/auditctl root:root 0750
/usr/sbin/auditd root:root 0750
/usr/sbin/ausearch root:root 0755
/usr/sbin/aureport root:root 0755
/usr/sbin/autrace root:root 0750
/usr/sbin/augenrules root:root 0750
Audit tools include but are not limited to vendor-provided and open-source
audit tools needed to successfully view and manipulate audit information
system activity and records. Audit tools include custom queries and report
generators.Rationale:Protecting audit information also includes identifying and protecting the
tools used to view and manipulate log data. Therefore, protecting audit
tools is necessary to prevent unauthorized operation on audit information.
SUSE operating systems providing tools to interface with audit information
will leverage user permissions and roles identifying the user accessing the
tools and the corresponding rights the user enjoys to make access decisions
regarding the access to audit tools. Remediation Shell script: (show)
#!/bin/bash
current_permissions_rules=$(grep "^/usr/sbin/au" /etc/permissions.local)
if [ ${#current_permissions_rules} -eq 0 ]
then
echo "There are no permission rules for audit information files and folders. We will add them"
echo "/usr/sbin/audispd root:root 0750" >> /etc/permissions.local
echo "/usr/sbin/auditctl root:root 0750" >> /etc/permissions.local
echo "/usr/sbin/auditd root:root 0750" >> /etc/permissions.local
echo "/usr/sbin/ausearch root:root 0755" >> /etc/permissions.local
echo "/usr/sbin/aureport root:root 0755" >> /etc/permissions.local
echo "/usr/sbin/autrace root:root 0750" >> /etc/permissions.local
echo "/usr/sbin/augenrules root:root 0750" >> /etc/permissions.local
fi
check_stats=$(chkstat /etc/permissions.local)
if [ ${#check_stats} -gt 0 ]
then
echo "Audit information files and folders don't have correct permissions.We will set them"
chkstat --set /etc/permissions.local
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | configure |
---|
- name: Configure permission for /usr/sbin/audispd
lineinfile:
path: /etc/permissions.local
create: true
regexp: ^\/usr\/sbin\/audispd\s+root.*
line: /usr/sbin/audispd root:root 0750
state: present
register: update_permissions_local_result_audispd
tags:
- CCE-85609-6
- DISA-STIG-SLES-15-030620
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- permissions_local_audit_binaries
- name: Correct file permissions after update /usr/sbin/audispd
shell: |
set -o pipefail chkstat --set --system
when: update_permissions_local_result_audispd.changed
tags:
- CCE-85609-6
- DISA-STIG-SLES-15-030620
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- permissions_local_audit_binaries
- name: Configure permission for /usr/sbin/auditctl
lineinfile:
path: /etc/permissions.local
create: true
regexp: ^\/usr\/sbin\/auditctl\s+root.*
line: /usr/sbin/auditctl root:root 0750
state: present
register: update_permissions_local_result_auditctl
tags:
- CCE-85609-6
- DISA-STIG-SLES-15-030620
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- permissions_local_audit_binaries
- name: Correct file permissions after update /usr/sbin/auditctl
shell: |
set -o pipefail chkstat --set --system
when: update_permissions_local_result_auditctl.changed
tags:
- CCE-85609-6
- DISA-STIG-SLES-15-030620
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- permissions_local_audit_binaries
- name: Configure permission for /usr/sbin/auditd
lineinfile:
path: /etc/permissions.local
create: true
regexp: ^\/usr\/sbin\/auditd\s+root.*
line: /usr/sbin/auditd root:root 0750
state: present
register: update_permissions_local_result_auditd
tags:
- CCE-85609-6
- DISA-STIG-SLES-15-030620
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- permissions_local_audit_binaries
- name: Correct file permissions after update /usr/sbin/auditd
shell: |
set -o pipefail chkstat --set --system
when: update_permissions_local_result_auditd.changed
tags:
- CCE-85609-6
- DISA-STIG-SLES-15-030620
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- permissions_local_audit_binaries
- name: Configure permission for /usr/sbin/ausearch
lineinfile:
path: /etc/permissions.local
create: true
regexp: ^\/usr\/sbin\/ausearch\s+root.*
line: /usr/sbin/ausearch root:root 0755
state: present
register: update_permissions_local_result_ausearch
tags:
- CCE-85609-6
- DISA-STIG-SLES-15-030620
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- permissions_local_audit_binaries
- name: Correct file permissions after update /usr/sbin/ausearch
shell: |
set -o pipefail chkstat --set --system
when: update_permissions_local_result_ausearch.changed
tags:
- CCE-85609-6
- DISA-STIG-SLES-15-030620
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- permissions_local_audit_binaries
- name: Configure permission for /usr/sbin/aureport
lineinfile:
path: /etc/permissions.local
create: true
regexp: ^\/usr\/sbin\/aureport\s+root.*
line: /usr/sbin/aureport root:root 0755
state: present
register: update_permissions_local_result_aureport
tags:
- CCE-85609-6
- DISA-STIG-SLES-15-030620
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- permissions_local_audit_binaries
- name: Correct file permissions after update /usr/sbin/aureport
shell: |
set -o pipefail chkstat --set --system
when: update_permissions_local_result_aureport.changed
tags:
- CCE-85609-6
- DISA-STIG-SLES-15-030620
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- permissions_local_audit_binaries
- name: Configure permission for /usr/sbin/autrace
lineinfile:
path: /etc/permissions.local
create: true
regexp: ^\/usr\/sbin\/autrace\s+root.*
line: /usr/sbin/autrace root:root 0750
state: present
register: update_permissions_local_result_autrace
tags:
- CCE-85609-6
- DISA-STIG-SLES-15-030620
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- permissions_local_audit_binaries
- name: Correct file permissions after update /usr/sbin/autrace
shell: |
set -o pipefail chkstat --set --system
when: update_permissions_local_result_autrace.changed
tags:
- CCE-85609-6
- DISA-STIG-SLES-15-030620
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- permissions_local_audit_binaries
- name: Configure permission for /usr/sbin/augenrules
lineinfile:
path: /etc/permissions.local
create: true
regexp: ^\/usr\/sbin\/augenrules\s+root.*
line: /usr/sbin/augenrules root:root 0750
state: present
register: update_permissions_local_result_augenrules
tags:
- CCE-85609-6
- DISA-STIG-SLES-15-030620
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- permissions_local_audit_binaries
- name: Correct file permissions after update /usr/sbin/augenrules
shell: |
set -o pipefail chkstat --set --system
when: update_permissions_local_result_augenrules.changed
tags:
- CCE-85609-6
- DISA-STIG-SLES-15-030620
- configure_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- permissions_local_audit_binaries
|
Verify that Local Logs of the audit Daemon are not World-Readable
[ref]ruleFiles containing sensitive informations should be protected by restrictive
permissions. Most of the time, there is no need that these files need to bei
read by any non-root user.
Check that "permissions.local" file contains the correct permissions rules with the following command:
# grep -i audit /etc/permissions.local
/var/log/audit/ root:root 600
/var/log/audit/audit.log root:root 600
/etc/audit/audit.rules root:root 640
/etc/audit/rules.d/audit.rules root:root 640 Rationale:Without the capability to restrict which roles and individuals can select
which events are audited, unauthorized personnel may be able to prevent the
auditing of critical events. Misconfigured audits may degrade the system's
performance by overwhelming the audit log. Misconfigured audits may also
make it more difficult to establish, correlate, and investigate the events
relating to an incident or identify those responsible for one. |
Restrict Programs from Dangerous Execution Patterns
[ref]groupThe recommendations in this section are designed to
ensure that the system's features to protect against potentially
dangerous program execution are activated.
These protections are applied at the system initialization or
kernel level, and defend against certain types of badly-configured
or compromised programs. |
contains 2 rules |
Enable ExecShield
[ref]groupExecShield describes kernel features that provide
protection against exploitation of memory corruption errors such as buffer
overflows. These features include random placement of the stack and other
memory regions, prevention of execution in memory that should only hold data,
and special handling of text buffers. These protections are enabled by default
on 32-bit systems and controlled through sysctl variables
kernel.exec-shield and kernel.randomize_va_space . On the latest
64-bit systems, kernel.exec-shield cannot be enabled or disabled with
sysctl . |
contains 2 rules |
Restrict Exposed Kernel Pointer Addresses Access
[ref]ruleTo set the runtime status of the kernel.kptr_restrict kernel parameter, run the following command: $ sudo sysctl -w kernel.kptr_restrict=1
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : kernel.kptr_restrict = 1 Rationale:Exposing kernel pointers (through procfs or seq_printf() ) exposes
kernel writeable structures that can contain functions pointers. If a write vulnereability occurs
in the kernel allowing a write access to any of this structure, the kernel can be compromise. This
option disallow any program withtout the CAP_SYSLOG capability from getting the kernel pointers addresses,
replacing them with 0. Identifiers:
CCE-83299-8 References:
BP28(R23), CCI-002824, CCI-000366, CIP-002-3 R1.1, CIP-002-3 R1.2, CIP-003-3 R5.1.1, CIP-003-3 R5.3, CIP-004-3 4.1, CIP-004-3 4.2, CIP-004-3 R2.2.3, CIP-004-3 R2.2.4, CIP-004-3 R2.3, CIP-004-3 R4, CIP-005-3a R1, CIP-005-3a R1.1, CIP-005-3a R1.2, CIP-007-3 R3, CIP-007-3 R3.1, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, CIP-007-3 R8.4, CIP-009-3 R.1.1, CIP-009-3 R4, SC-30, SC-30(2), SC-30(5), CM-6(a), SRG-OS-000132-GPOS-00067, SRG-OS-000433-GPOS-00192, SRG-OS-000480-GPOS-00227, SLES-15-010540, SV-234861r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: Ensure sysctl kernel.kptr_restrict is set to 1
sysctl:
name: kernel.kptr_restrict
value: '1'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83299-8
- DISA-STIG-SLES-15-010540
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-30
- NIST-800-53-SC-30(2)
- NIST-800-53-SC-30(5)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_kptr_restrict
|
Enable Randomized Layout of Virtual Address Space
[ref]ruleTo set the runtime status of the kernel.randomize_va_space kernel parameter, run the following command: $ sudo sysctl -w kernel.randomize_va_space=2
To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d : kernel.randomize_va_space = 2 Rationale:Address space layout randomization (ASLR) makes it more difficult for an
attacker to predict the location of attack code they have introduced into a
process's address space during an attempt at exploitation. Additionally,
ASLR makes it more difficult for an attacker to know the location of
existing code in order to re-purpose it using return oriented programming
(ROP) techniques. Identifiers:
CCE-83300-4 References:
BP28(R23), 1.6.3, 3.1.7, CCI-000366, CCI-002824, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), CIP-002-3 R1.1, CIP-002-3 R1.2, CIP-003-3 R5.1.1, CIP-003-3 R5.3, CIP-004-3 4.1, CIP-004-3 4.2, CIP-004-3 R2.2.3, CIP-004-3 R2.2.4, CIP-004-3 R2.3, CIP-004-3 R4, CIP-005-3a R1, CIP-005-3a R1.1, CIP-005-3a R1.2, CIP-007-3 R3, CIP-007-3 R3.1, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, CIP-007-3 R8.4, CIP-009-3 R.1.1, CIP-009-3 R4, SC-30, SC-30(2), CM-6(a), SRG-OS-000433-GPOS-00193, SRG-OS-000480-GPOS-00227, SLES-15-010550, SV-234862r622137_rule Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Reboot: | true |
---|
Strategy: | disable |
---|
- name: Ensure sysctl kernel.randomize_va_space is set to 2
sysctl:
name: kernel.randomize_va_space
value: '2'
state: present
reload: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83300-4
- DISA-STIG-SLES-15-010550
- NIST-800-171-3.1.7
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-30
- NIST-800-53-SC-30(2)
- disable_strategy
- low_complexity
- medium_disruption
- medium_severity
- reboot_required
- sysctl_kernel_randomize_va_space
|
Services
[ref]groupThe best protection against vulnerable software is running less software. This section describes how to review
the software which SUSE Linux Enterprise 15 installs on a system and disable software which is not needed. It
then enumerates the software packages installed on a default SUSE Linux Enterprise 15 system and provides guidance about which
ones can be safely disabled.
SUSE Linux Enterprise 15 provides a convenient minimal install option that essentially installs the bare necessities for a functional
system. When building SUSE Linux Enterprise 15 systems, it is highly recommended to select the minimal packages and then build up
the system from there. |
contains 28 rules |
Base Services
[ref]groupThis section addresses the base services that are installed on a
SUSE Linux Enterprise 15 default installation which are not covered in other
sections. Some of these services listen on the network and
should be treated with particular discretion. Other services are local
system utilities that may or may not be extraneous. In general, system services
should be disabled if not required. |
contains 1 rule |
Disable KDump Kernel Crash Analyzer (kdump)
[ref]ruleThe kdump service provides a kernel crash dump analyzer. It uses the kexec
system call to boot a secondary kernel ("capture" kernel) following a system
crash, which can load information from the crashed kernel for analysis.
The kdump service can be disabled with the following command:
$ sudo systemctl mask --now kdump.service Rationale:Kernel core dumps may contain the full contents of system memory at the
time of the crash. Kernel core dumps consume a considerable amount of disk
space and may result in denial of service by exhausting the available space
on the target file system partition. Unless the system is used for kernel
development or testing, there is little need to run the kdump service. Identifiers:
CCE-85638-5 References:
11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000366, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, FMT_SMF_EXT.1.1, SRG-OS-000480-GPOS-00227, SLES-15-040190, SV-235003r622137_rule Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'kdump.service'
"$SYSTEMCTL_EXEC" disable 'kdump.service'
"$SYSTEMCTL_EXEC" mask 'kdump.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" list-unit-files | grep -q '^kdump.socket'; then
"$SYSTEMCTL_EXEC" stop 'kdump.socket'
"$SYSTEMCTL_EXEC" mask 'kdump.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'kdump.service' || true
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
- name: Disable service kdump
block:
- name: Gather the service facts
service_facts: null
- name: Disable service kdump
systemd:
name: kdump.service
enabled: 'no'
state: stopped
masked: 'yes'
when: '"kdump.service" in ansible_facts.services'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85638-5
- DISA-STIG-SLES-15-040190
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_kdump_disabled
- name: Unit Socket Exists - kdump.socket
command: systemctl list-unit-files kdump.socket
args:
warn: false
register: socket_file_exists
changed_when: false
ignore_errors: true
check_mode: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85638-5
- DISA-STIG-SLES-15-040190
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_kdump_disabled
- name: Disable socket kdump
systemd:
name: kdump.socket
enabled: 'no'
state: stopped
masked: 'yes'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"kdump.socket" in socket_file_exists.stdout_lines[1]'
tags:
- CCE-85638-5
- DISA-STIG-SLES-15-040190
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_kdump_disabled
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include disable_kdump
class disable_kdump {
service {'kdump':
enable => false,
ensure => 'stopped',
}
}
|
FTP Server
[ref]groupFTP is a common method for allowing remote access to
files. Like telnet, the FTP protocol is unencrypted, which means
that passwords and other data transmitted during the session can be
captured and that the session is vulnerable to hijacking.
Therefore, running the FTP server software is not recommended.
However, there are some FTP server configurations which may
be appropriate for some environments, particularly those which
allow only read-only anonymous access as a means of downloading
data available to the public. |
contains 1 rule |
Disable vsftpd if Possible
[ref]groupTo minimize attack surface, disable vsftpd if at all
possible. |
contains 1 rule |
Uninstall vsftpd Package
[ref]ruleThe vsftpd package can be removed with the following command: $ sudo zypper remove vsftpd Rationale:Removing the vsftpd package decreases the risk of its
accidental activation. Identifiers:
CCE-85700-3 References:
2.2.8, 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, CCI-000197, CCI-000366, CCI-000381, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), IA-5(1)(c), IA-5(1).1(v), CM-7, CM-7.1(ii), PR.IP-1, PR.PT-3, SRG-OS-000074-GPOS-00042, SRG-OS-000095-GPOS-00049, SRG-OS-000480-GPOS-00227, SLES-15-010030, SV-234804r622137_rule Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove vsftpd
# from the system, and may remove any packages
# that depend on vsftpd. Execute this
# remediation AFTER testing on a non-production
# system!
zypper remove -y "vsftpd"
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
- name: Ensure vsftpd is removed
package:
name: vsftpd
state: absent
tags:
- CCE-85700-3
- DISA-STIG-SLES-15-010030
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-CM-7.1(ii)
- NIST-800-53-IA-5(1)(c)
- NIST-800-53-IA-5(1).1(v)
- disable_strategy
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- package_vsftpd_removed
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
include remove_vsftpd
class remove_vsftpd {
package { 'vsftpd':
ensure => 'purged',
}
}
|
Mail Server Software
[ref]groupMail servers are used to send and receive email over the network.
Mail is a very common service, and Mail Transfer Agents (MTAs) are obvious
targets of network attack.
Ensure that systems are not running MTAs unnecessarily,
and configure needed MTAs as defensively as possible.
Very few systems at any site should be configured to directly receive email over the
network. Users should instead use mail client programs to retrieve email
from a central server that supports protocols such as IMAP or POP3.
However, it is normal for most systems to be independently capable of sending email,
for instance so that cron jobs can report output to an administrator.
Most MTAs, including Postfix, support a submission-only mode in which mail can be sent from
the local system to a central site MTA (or directly delivered to a local account),
but the system still cannot receive mail directly over a network.
The alternatives program in SUSE Linux Enterprise 15 permits selection of other mail server software
(such as Sendmail), but Postfix is the default and is preferred.
Postfix was coded with security in mind and can also be more effectively contained by
SELinux as its modular design has resulted in separate processes performing specific actions.
More information is available on its website,
http://www.postfix.org. |
contains 1 rule |
Configure SMTP For Mail Clients
[ref]groupThis section discusses settings for Postfix in a submission-only
e-mail configuration. |
contains 1 rule |
Configure System to Forward All Mail For The Root Account
[ref]ruleMake sure that mails delivered to root user are forwarded to a monitored
email address. Make sure that the address
system.administrator@mail.mil is a valid email address
reachable from the system in question. Use the following command to
configure the alias:
$ sudo echo "root: system.administrator@mail.mil" >> /etc/aliases
$ sudo newaliases Rationale:A number of system services utilize email messages sent to the root user to
notify system administrators of active or impending issues. These messages must
be forwarded to at least one monitored email address. Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
var_postfix_root_mail_alias="system.administrator@mail.mil"
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/aliases"; then
sed_command+=('--follow-symlinks')
fi
# If the cce arg is empty, CCE is not assigned.
if [ -z "CCE-85605-4" ]; then
cce="CCE"
else
cce="CCE-85605-4"
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^root")
# shellcheck disable=SC2059
printf -v formatted_output "%s: %s" "$stripped_key" "$var_postfix_root_mail_alias"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^root\\>" "/etc/aliases"; then
"${sed_command[@]}" "s/^root\\>.*/$formatted_output/gi" "/etc/aliases"
else
# \n is precaution for case where file ends without trailing newline
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/aliases" >> "/etc/aliases"
printf '%s\n' "$formatted_output" >> "/etc/aliases"
fi
newaliases
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | configure |
---|
- name: XCCDF Value var_postfix_root_mail_alias # promote to variable
set_fact:
var_postfix_root_mail_alias: !!str system.administrator@mail.mil
tags:
- always
- name: Make sure that that "/etc/aliases" has a defined value for root
lineinfile:
path: /etc/aliases
line: 'root: {{ var_postfix_root_mail_alias }}'
regexp: ^(?:[rR][oO][oO][tT]|"[rR][oO][oO][tT]")\s*:\s*(.+)$
create: true
state: present
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85605-4
- DISA-STIG-SLES-15-030580
- NIST-800-53-CM-6(a)
- configure_strategy
- low_complexity
- low_disruption
- low_severity
- no_reboot_needed
- postfix_client_configure_mail_alias
|
NFS and RPC
[ref]groupThe Network File System is a popular distributed filesystem for
the Unix environment, and is very widely deployed. This section discusses the
circumstances under which it is possible to disable NFS and its dependencies,
and then details steps which should be taken to secure
NFS's configuration. This section is relevant to systems operating as NFS
clients, as well as to those operating as NFS servers. |
contains 2 rules |
Configure NFS Clients
[ref]groupThe steps in this section are appropriate for systems which operate as NFS clients. |
contains 2 rules |
Mount Remote Filesystems with Restrictive Options
[ref]groupEdit the file /etc/fstab . For each filesystem whose type
(column 3) is nfs or nfs4 , add the text
,nodev,nosuid to the list of mount options in column 4. If
appropriate, also add ,noexec .
See the section titled "Restrict Partition Mount Options" for a description of
the effects of these options. In general, execution of files mounted via NFS
should be considered risky because of the possibility that an adversary could
intercept the request and substitute a malicious file. Allowing setuid files to
be executed from remote servers is particularly risky, both for this reason and
because it requires the clients to extend root-level trust to the NFS
server. |
contains 2 rules |
Mount Remote Filesystems with noexec
[ref]ruleAdd the noexec option to the fourth column of /etc/fstab for the line which controls mounting of
any NFS mounts. Rationale:The noexec mount option causes the system not to execute binary files. This option must be used
for mounting any file system not containing approved binary files as they may be incompatible. Executing
files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized
administrative access. Identifiers:
CCE-85636-9 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-000366, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, AC-6, AC-6(8), AC-6(10), CM-6(a), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, SLES-15-040170, SV-235001r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
vfstype_points=()
readarray -t vfstype_points < <(grep -E "[[:space:]]nfs[4]?[[:space:]]" /etc/fstab | awk '{print $2}')
for vfstype_point in "${vfstype_points[@]}"
do
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" $vfstype_point)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if [ "$(grep -c "$mount_point_match_regexp" /etc/fstab)" -eq 0 ]; then
# runtime opts without some automatic kernel/userspace-added defaults
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 | awk '{print $4}' \
| sed -E "s/(rw|defaults|seclabel|noexec)(,|$)//g;s/,$//")
[ "$previous_mount_opts" ] && previous_mount_opts+=","
echo " $vfstype_point nfs4 defaults,${previous_mount_opts}noexec 0 0" >> /etc/fstab
# If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
elif [ "$(grep "$mount_point_match_regexp" /etc/fstab | grep -c "noexec")" -eq 0 ]; then
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,noexec|" /etc/fstab
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Strategy: | configure |
---|
- name: Get nfs and nfs4 mount points, that don't have noexec
command: findmnt --fstab --types nfs,nfs4 -O nonoexec -n
register: points_register
check_mode: false
changed_when: false
failed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85636-9
- DISA-STIG-SLES-15-040170
- NIST-800-53-AC-6
- NIST-800-53-AC-6(10)
- NIST-800-53-AC-6(8)
- NIST-800-53-CM-6(a)
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- mount_option_noexec_remote_filesystems
- no_reboot_needed
- name: Add noexec to nfs and nfs4 mount points
mount:
path: '{{ item.split()[0] }}'
src: '{{ item.split()[1] }}'
fstype: '{{ item.split()[2] }}'
state: mounted
opts: '{{ item.split()[3] }},noexec'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- (points_register.stdout | length > 0)
with_items: '{{ points_register.stdout_lines }}'
tags:
- CCE-85636-9
- DISA-STIG-SLES-15-040170
- NIST-800-53-AC-6
- NIST-800-53-AC-6(10)
- NIST-800-53-AC-6(8)
- NIST-800-53-CM-6(a)
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- mount_option_noexec_remote_filesystems
- no_reboot_needed
|
Mount Remote Filesystems with nosuid
[ref]ruleAdd the nosuid option to the fourth column of /etc/fstab for the line which controls mounting of
any NFS mounts. Rationale:NFS mounts should not present suid binaries to users. Only vendor-supplied suid executables
should be installed to their default location on the local filesystem. Identifiers:
CCE-85635-1 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-000366, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, AC-6, AC-6(1), CM6(a), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, SLES-15-040160, SV-235000r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
vfstype_points=()
readarray -t vfstype_points < <(grep -E "[[:space:]]nfs[4]?[[:space:]]" /etc/fstab | awk '{print $2}')
for vfstype_point in "${vfstype_points[@]}"
do
mount_point_match_regexp="$(printf "[[:space:]]%s[[:space:]]" $vfstype_point)"
# If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
if [ "$(grep -c "$mount_point_match_regexp" /etc/fstab)" -eq 0 ]; then
# runtime opts without some automatic kernel/userspace-added defaults
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 | awk '{print $4}' \
| sed -E "s/(rw|defaults|seclabel|nosuid)(,|$)//g;s/,$//")
[ "$previous_mount_opts" ] && previous_mount_opts+=","
echo " $vfstype_point nfs4 defaults,${previous_mount_opts}nosuid 0 0" >> /etc/fstab
# If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
elif [ "$(grep "$mount_point_match_regexp" /etc/fstab | grep -c "nosuid")" -eq 0 ]; then
previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,nosuid|" /etc/fstab
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Strategy: | configure |
---|
- name: Get nfs and nfs4 mount points, that don't have nosuid
command: findmnt --fstab --types nfs,nfs4 -O nonosuid -n
register: points_register
check_mode: false
changed_when: false
failed_when: false
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85635-1
- DISA-STIG-SLES-15-040160
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM6(a)
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- mount_option_nosuid_remote_filesystems
- no_reboot_needed
- name: Add nosuid to nfs and nfs4 mount points
mount:
path: '{{ item.split()[0] }}'
src: '{{ item.split()[1] }}'
fstype: '{{ item.split()[2] }}'
state: mounted
opts: '{{ item.split()[3] }},nosuid'
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- (points_register.stdout | length > 0)
with_items: '{{ points_register.stdout_lines }}'
tags:
- CCE-85635-1
- DISA-STIG-SLES-15-040160
- NIST-800-53-AC-6
- NIST-800-53-AC-6(1)
- NIST-800-53-CM6(a)
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- mount_option_nosuid_remote_filesystems
- no_reboot_needed
|
Network Time Protocol
[ref]groupThe Network Time Protocol is used to manage the system
clock over a network. Computer clocks are not very accurate, so
time will drift unpredictably on unmanaged systems. Central time
protocols can be used both to ensure that time is consistent among
a network of systems, and that their time is consistent with the
outside world.
If every system on a network reliably reports the same time, then it is much
easier to correlate log messages in case of an attack. In addition, a number of
cryptographic protocols (such as Kerberos) use timestamps to prevent certain
types of attacks. If your network does not have synchronized time, these
protocols may be unreliable or even unusable.
Depending on the specifics of the network, global time accuracy may be just as
important as local synchronization, or not very important at all. If your
network is connected to the Internet, using a public timeserver (or one
provided by your enterprise) provides globally accurate timestamps which may be
essential in investigating or responding to an attack which originated outside
of your network.
A typical network setup involves a small number of internal systems operating
as NTP servers, and the remainder obtaining time information from those
internal servers.
There is a choice between the daemons ntpd and chronyd , which
are available from the repositories in the ntp and chrony
packages respectively.
The default chronyd daemon can work well when external time references
are only intermittently accesible, can perform well even when the network is
congested for longer periods of time, can usually synchronize the clock faster
and with better time accuracy, and quickly adapts to sudden changes in the rate
of the clock, for example, due to changes in the temperature of the crystal
oscillator. Chronyd should be considered for all systems which are
frequently suspended or otherwise intermittently disconnected and reconnected
to a network. Mobile and virtual systems for example.
The ntpd NTP daemon fully supports NTP protocol version 4 (RFC 5905),
including broadcast, multicast, manycast clients and servers, and the orphan
mode. It also supports extra authentication schemes based on public-key
cryptography (RFC 5906). The NTP daemon (ntpd ) should be considered
for systems which are normally kept permanently on. Systems which are required
to use broadcast or multicast IP, or to perform authentication of packets with
the Autokey protocol, should consider using ntpd .
Refer to
https://docs.fedoraproject.org/en-US/fedora/rawhide/system-administrators-guide/servers/Configuring_NTP_Using_the_chrony_Suite/
for more detailed comparison of features of chronyd
and ntpd daemon features respectively, and for further guidance how to
choose between the two NTP daemons.
The upstream manual pages at
http://chrony.tuxfamily.org/manual.html for
chronyd and
http://www.ntp.org for ntpd provide additional
information on the capabilities and configuration of each of the NTP daemons. |
contains 1 rule |
Configure Time Service Maxpoll Interval
[ref]ruleThe maxpoll should be configured to
16 in /etc/ntp.conf or
/etc/chrony.conf to continuously poll time servers. To configure
maxpoll in /etc/ntp.conf or /etc/chrony.conf
add the following:
maxpoll 16 Rationale:Inaccurate time stamps make it more difficult to correlate
events and can lead to an inaccurate analysis. Determining the correct
time a particular event occurred on a system is critical when conducting
forensic analysis and investigating system events. Sources outside the
configured acceptable allowance (drift) may be inaccurate. Identifiers:
CCE-83287-3 References:
1, 14, 15, 16, 3, 5, 6, APO11.04, BAI03.05, DSS05.04, DSS05.07, MEA02.01, CCI-001891, CCI-002046, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, CM-6(a), AU-8(1)(b), PR.PT-1, SRG-OS-000355-GPOS-00143, SRG-OS-000356-GPOS-00144, SRG-OS-000359-GPOS-00146, SLES-15-010400, SV-234849r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q chrony || rpm --quiet -q ntp; }; then
var_time_service_set_maxpoll="16"
config_file="/etc/ntp.conf"
/usr/sbin/pidof ntpd || config_file="/etc/chrony.conf"
# Set maxpoll values to var_time_service_set_maxpoll
sed -i "s/^\(server.*maxpoll\) [0-9][0-9]*\(.*\)$/\1 $var_time_service_set_maxpoll \2/" "$config_file"
# Add maxpoll to server entries without maxpoll
grep "^server" "$config_file" | grep -v maxpoll | while read -r line ; do
sed -i "s/$line/& maxpoll $var_time_service_set_maxpoll/" "$config_file"
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83287-3
- DISA-STIG-SLES-15-010400
- NIST-800-53-AU-8(1)(b)
- NIST-800-53-CM-6(a)
- chronyd_or_ntpd_set_maxpoll
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: XCCDF Value var_time_service_set_maxpoll # promote to variable
set_fact:
var_time_service_set_maxpoll: !!str 16
tags:
- always
- name: Check that /etc/ntp.conf exist
stat:
path: /etc/ntp.conf
register: ntp_conf_exist_result
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"chrony" in ansible_facts.packages or "ntp" in ansible_facts.packages'
tags:
- CCE-83287-3
- DISA-STIG-SLES-15-010400
- NIST-800-53-AU-8(1)(b)
- NIST-800-53-CM-6(a)
- chronyd_or_ntpd_set_maxpoll
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Check that /etc/chrony.conf exist
stat:
path: /etc/chrony.conf
register: chrony_conf_exist_result
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"chrony" in ansible_facts.packages or "ntp" in ansible_facts.packages'
tags:
- CCE-83287-3
- DISA-STIG-SLES-15-010400
- NIST-800-53-AU-8(1)(b)
- NIST-800-53-CM-6(a)
- chronyd_or_ntpd_set_maxpoll
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Update the maxpoll values in /etc/ntp.conf
lineinfile:
path: /etc/ntp.conf
regex: ^(server.*maxpoll) [0-9]+(\s+.*)$
line: \1 {{ var_time_service_set_maxpoll }}\2
backrefs: true
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"chrony" in ansible_facts.packages or "ntp" in ansible_facts.packages'
- ntp_conf_exist_result.stat.exists
tags:
- CCE-83287-3
- DISA-STIG-SLES-15-010400
- NIST-800-53-AU-8(1)(b)
- NIST-800-53-CM-6(a)
- chronyd_or_ntpd_set_maxpoll
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Update the maxpoll values in /etc/chrony.conf
lineinfile:
path: /etc/chrony.conf
regex: ^(server.*maxpoll) [0-9]+(\s+.*)$
line: \1 {{ var_time_service_set_maxpoll }}\2
backrefs: true
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"chrony" in ansible_facts.packages or "ntp" in ansible_facts.packages'
- chrony_conf_exist_result.stat.exists
tags:
- CCE-83287-3
- DISA-STIG-SLES-15-010400
- NIST-800-53-AU-8(1)(b)
- NIST-800-53-CM-6(a)
- chronyd_or_ntpd_set_maxpoll
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set the maxpoll values in /etc/ntp.conf
lineinfile:
path: /etc/ntp.conf
regex: (^server\s+((?!maxpoll).)*)$
line: \1 maxpoll {{ var_time_service_set_maxpoll }}\n
backrefs: true
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"chrony" in ansible_facts.packages or "ntp" in ansible_facts.packages'
- ntp_conf_exist_result.stat.exists
tags:
- CCE-83287-3
- DISA-STIG-SLES-15-010400
- NIST-800-53-AU-8(1)(b)
- NIST-800-53-CM-6(a)
- chronyd_or_ntpd_set_maxpoll
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- name: Set the maxpoll values in /etc/chrony.conf
lineinfile:
path: /etc/chrony.conf
regex: (^server\s+((?!maxpoll).)*)$
line: \1 maxpoll {{ var_time_service_set_maxpoll }}\n
backrefs: true
when:
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- '"chrony" in ansible_facts.packages or "ntp" in ansible_facts.packages'
- chrony_conf_exist_result.stat.exists
tags:
- CCE-83287-3
- DISA-STIG-SLES-15-010400
- NIST-800-53-AU-8(1)(b)
- NIST-800-53-CM-6(a)
- chronyd_or_ntpd_set_maxpoll
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
|
Obsolete Services
[ref]groupThis section discusses a number of network-visible
services which have historically caused problems for system
security, and for which disabling or severely limiting the service
has been the best available guidance for some time. As a result of
this, many of these services are not installed as part of SUSE Linux Enterprise 15
by default.
Organizations which are running these services should
switch to more secure equivalents as soon as possible.
If it remains absolutely necessary to run one of
these services for legacy reasons, care should be taken to restrict
the service as much as possible, for instance by configuring host
firewall software such as iptables to restrict access to the
vulnerable service to only those remote hosts which have a known
need to use it. |
contains 3 rules |
Rlogin, Rsh, and Rexec
[ref]groupThe Berkeley r-commands are legacy services which
allow cleartext remote access and have an insecure trust
model. |
contains 2 rules |
Remove Host-Based Authentication Files
[ref]ruleThe shosts.equiv file list remote hosts
and users that are trusted by the local system.
To remove these files, run the following command to delete them from any
location:
$ sudo rm /[path]/[to]/[file]/shosts.equiv Rationale:The shosts.equiv files are used to configure host-based authentication for the
system via SSH. Host-based authentication is not sufficient for preventing
unauthorized access to the system, as it does not require interactive
identification and authentication of a connection request, or for the use of
two-factor authentication. Remediation Shell script: (show)
# Identify local mounts
MOUNT_LIST=$(df --local | awk '{ print $6 }')
# Find file on each listed mount point
for cur_mount in ${MOUNT_LIST}
do
find ${cur_mount} -xdev -type f -name "shosts.equiv" -exec rm -f {} \;
done
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- block:
- name: Find local mount points
shell: |
set -o pipefail
df --local | awk '{print $6}' | grep -v Mounted | grep -v '^/dev' || true
register: local_mount_points
- name: Detect the shosts.equiv files on the system
find:
paths: '{{ item }}'
recurse: true
patterns:
- shosts.equiv
file_type: file
check_mode: false
with_items: '{{ local_mount_points.stdout_lines }}'
register: shosts_equiv_locations
- name: Remove shosts.equiv Files
file:
path: '{{ item.path }}'
state: absent
with_items: '{{ shosts_equiv_locations.results | map(attribute=''files'') |
list }}'
when: shosts_equiv_locations is success
tags:
- CCE-85622-9
- DISA-STIG-SLES-15-040030
- high_severity
- low_complexity
- low_disruption
- no_host_based_files
- no_reboot_needed
- restrict_strategy
|
Remove User Host-Based Authentication Files
[ref]ruleThe ~/.shosts (in each user's home directory) files
list remote hosts and users that are trusted by the
local system. To remove these files, run the following command
to delete them from any location:
$ sudo find / -name '.shosts' -type f -delete Rationale:The .shosts files are used to configure host-based authentication for
individual users or the system via SSH. Host-based authentication is not
sufficient for preventing unauthorized access to the system, as it does not
require interactive identification and authentication of a connection request,
or for the use of two-factor authentication. Remediation Shell script: (show)
# Identify local mounts
MOUNT_LIST=$(df --local | awk '{ print $6 }')
# Find file on each listed mount point
for cur_mount in ${MOUNT_LIST}
do
find ${cur_mount} -xdev -type f -name ".shosts" -exec rm -f {} \;
done
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- block:
- name: Find local mount points
shell: |
set -o pipefail
df --local | awk '{print $6}' | grep -v Mounted | grep -v '^/dev' || true
register: local_mount_points
- name: Detect the .shosts files on the system
find:
paths: '{{ item }}'
recurse: true
patterns:
- .shosts
hidden: true
file_type: file
check_mode: false
with_items: '{{ local_mount_points.stdout_lines }}'
register: shosts_locations
- name: Remove .shosts Files
file:
path: '{{ item.path }}'
state: absent
with_items: '{{ shosts_locations.results | map(attribute=''files'') | list }}'
when: shosts_locations is success
tags:
- CCE-85621-1
- DISA-STIG-SLES-15-040020
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- no_user_host_based_files
- restrict_strategy
|
Telnet
[ref]groupThe telnet protocol does not provide confidentiality or integrity
for information transmitted on the network. This includes authentication
information such as passwords. Organizations which use telnet should be
actively working to migrate to a more secure protocol. |
contains 1 rule |
Uninstall telnet-server Package
[ref]ruleThe telnet-server package can be removed with the following command:
$ sudo zypper remove telnet-server Rationale:It is detrimental for operating systems to provide, or install by default,
functionality exceeding requirements or mission objectives. These
unnecessary capabilities are often overlooked and therefore may remain
unsecure. They increase the risk to the platform by providing additional
attack vectors.
The telnet service provides an unencrypted remote access service which does
not provide for the confidentiality and integrity of user passwords or the
remote session. If a privileged user were to login using this service, the
privileged user password could be compromised.
Removing the telnet-server package decreases the risk of the
telnet service's accidental (or intentional) activation. Identifiers:
CCE-83273-3 References:
BP28(R1), 2.2.19, 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000381, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000095-GPOS-00049, SLES-15-010180, SV-234818r622137_rule Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
# CAUTION: This remediation script will remove telnet-server
# from the system, and may remove any packages
# that depend on telnet-server. Execute this
# remediation AFTER testing on a non-production
# system!
zypper remove -y "telnet-server"
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
- name: Ensure telnet-server is removed
package:
name: telnet-server
state: absent
tags:
- CCE-83273-3
- DISA-STIG-SLES-15-010180
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- disable_strategy
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- package_telnet-server_removed
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | disable |
---|
include remove_telnet-server
class remove_telnet-server {
package { 'telnet-server':
ensure => 'purged',
}
}
|
SSH Server
[ref]groupThe SSH protocol is recommended for remote login and
remote file transfer. SSH provides confidentiality and integrity
for data exchanged between two systems, as well as server
authentication, through the use of public key cryptography. The
implementation included with the system is called OpenSSH, and more
detailed documentation is available from its website,
https://www.openssh.com.
Its server program is called sshd and provided by the RPM package
openssh-server . |
contains 17 rules |
Configure OpenSSH Server if Necessary
[ref]groupIf the system needs to act as an SSH server, then
certain changes should be made to the OpenSSH daemon configuration
file /etc/ssh/sshd_config . The following recommendations can be
applied to this file. See the sshd_config(5) man page for more
detailed information. |
contains 14 rules |
Disable Compression Or Set Compression to delayed
[ref]ruleCompression is useful for slow network connections over long
distances but can cause performance issues on local LANs. If use of compression
is required, it should be enabled only after a user has authenticated; otherwise,
it should be disabled. To disable compression or delay compression until after
a user has successfully authenticated, add or correct the following line in the
/etc/ssh/sshd_config file:
Compression no Rationale:If compression is allowed in an SSH connection prior to authentication,
vulnerabilities in the compression software could result in compromise of the
system from an unauthenticated connection, potentially with root privileges. Identifiers:
CCE-85647-6 References:
11, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.1.12, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, AC-17(a), CM-7(a), CM-7(b), CM-6(a), PR.IP-1, SRG-OS-000480-GPOS-00227, SLES-15-040280, SV-235012r622137_rule, SRG-OS-000480-VMM-002000 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
var_sshd_disable_compression="no"
# Test if the config_file is a symbolic link. If so, use --follow-symlinks with sed.
# Otherwise, regular sed command will do.
sed_command=('sed' '-i')
if test -L "/etc/ssh/sshd_config"; then
sed_command+=('--follow-symlinks')
fi
# If the cce arg is empty, CCE is not assigned.
if [ -z "CCE-85647-6" ]; then
cce="CCE"
else
cce="CCE-85647-6"
fi
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^Compression")
# shellcheck disable=SC2059
printf -v formatted_output "%s %s" "$stripped_key" "$var_sshd_disable_compression"
# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^Compression\\>" "/etc/ssh/sshd_config"; then
"${sed_command[@]}" "s/^Compression\\>.*/$formatted_output/gi" "/etc/ssh/sshd_config"
else
# \n is precaution for case where file ends without trailing newline
printf '\n# Per %s: Set %s in %s\n' "$cce" "$formatted_output" "/etc/ssh/sshd_config" >> "/etc/ssh/sshd_config"
printf '%s\n' "$formatted_output" >> "/etc/ssh/sshd_config"
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: XCCDF Value var_sshd_disable_compression # promote to variable
set_fact:
var_sshd_disable_compression: !!str no
tags:
- always
- name: Disable Compression Or Set Compression to delayed
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*Compression\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*Compression\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*Compression\s+
line: Compression {{ var_sshd_disable_compression }}
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85647-6
- DISA-STIG-SLES-15-040280
- NIST-800-171-3.1.12
- NIST-800-53-AC-17(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_disable_compression
|
Disable SSH Access via Empty Passwords
[ref]ruleTo explicitly disallow SSH login from accounts with
empty passwords, add or correct the following line in /etc/ssh/sshd_config :
PermitEmptyPasswords no
Any accounts with empty passwords should be disabled immediately, and PAM configuration
should prevent users from being able to assign themselves empty passwords.Rationale:Configuring this setting for the SSH daemon provides additional assurance
that remote login via SSH will require a password, even in the event of
misconfiguration elsewhere. Identifiers:
CCE-85667-4 References:
NT007(R17), 5.2.11, 11, 12, 13, 14, 15, 16, 18, 3, 5, 9, 5.5.6, APO01.06, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, 3.1.1, 3.1.5, CCI-000366, CCI-000766, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 5.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(b), CM-6.1(iv), PR.AC-4, PR.AC-6, PR.DS-5, PR.IP-1, PR.PT-3, FIA_UAU.1, SRG-OS-000106-GPOS-00053, SRG-OS-000480-GPOS-00229, SRG-OS-000480-GPOS-00227, SLES-15-040440, SV-235032r622137_rule, SRG-OS-000480-VMM-002000 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*PermitEmptyPasswords\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "PermitEmptyPasswords no" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "PermitEmptyPasswords no" >> "/etc/ssh/sshd_config"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Disable SSH Access via Empty Passwords
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*PermitEmptyPasswords\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*PermitEmptyPasswords\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*PermitEmptyPasswords\s+
line: PermitEmptyPasswords no
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85667-4
- CJIS-5.5.6
- DISA-STIG-SLES-15-040440
- NIST-800-171-3.1.1
- NIST-800-171-3.1.5
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- high_severity
- low_complexity
- low_disruption
- no_reboot_needed
- restrict_strategy
- sshd_disable_empty_passwords
|
Disable SSH Root Login
[ref]ruleThe root user should never be allowed to login to a
system directly over a network.
To disable root login via SSH, add or correct the following line
in /etc/ssh/sshd_config :
PermitRootLogin no Rationale:Even though the communications channel may be encrypted, an additional layer of
security is gained by extending the policy of not logging directly on as root.
In addition, logging in with a user-specific account provides individual
accountability of actions performed on the system and also helps to minimize
direct attack attempts on root's password. Identifiers:
CCE-85557-7 References:
BP28(R19), NT007(R21), 5.2.10, 1, 11, 12, 13, 14, 15, 16, 18, 3, 5, 5.5.6, APO01.06, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.02, DSS06.03, DSS06.06, DSS06.10, 3.1.1, 3.1.5, CCI-000366, CCI-000770, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.18.1.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-003-3 R5.1.1, CIP-003-3 R5.3, CIP-004-3 R2.2.3, CIP-004-3 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, AC-6(2), AC-17(a), IA-2, IA-2(5), CM-7(a), CM-7(b), CM-6(a), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.DS-5, PR.PT-3, FIA_UAU.1, SRG-OS-000109-GPOS-00056, SRG-OS-000480-GPOS-00227, SLES-15-020040, SV-234870r622137_rule, SRG-OS-000480-VMM-002000 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*PermitRootLogin\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "PermitRootLogin no" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "PermitRootLogin no" >> "/etc/ssh/sshd_config"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Disable SSH Root Login
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*PermitRootLogin\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*PermitRootLogin\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*PermitRootLogin\s+
line: PermitRootLogin no
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85557-7
- CJIS-5.5.6
- DISA-STIG-SLES-15-020040
- NIST-800-171-3.1.1
- NIST-800-171-3.1.5
- NIST-800-53-
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-6(2)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- NIST-800-53-IA-2
- NIST-800-53-IA-2(5)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_disable_root_login
|
Disable SSH Support for User Known Hosts
[ref]ruleSSH can allow system users to connect to systems if a cache of the remote
systems public keys is available. This should be disabled.
To ensure this behavior is disabled, add or correct the
following line in /etc/ssh/sshd_config :
IgnoreUserKnownHosts yes Rationale:Configuring this setting for the SSH daemon provides additional
assurance that remote login via SSH will require a password, even
in the event of misconfiguration elsewhere. Identifiers:
CCE-85642-7 References:
11, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.1.12, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, AC-17(a), CM-7(a), CM-7(b), CM-6(a), PR.IP-1, FIA_UAU.1, SRG-OS-000480-GPOS-00227, SLES-15-040230, SV-235007r622137_rule Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*IgnoreUserKnownHosts\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "IgnoreUserKnownHosts yes" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "IgnoreUserKnownHosts yes" >> "/etc/ssh/sshd_config"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Disable SSH Support for User Known Hosts
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*IgnoreUserKnownHosts\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*IgnoreUserKnownHosts\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*IgnoreUserKnownHosts\s+
line: IgnoreUserKnownHosts yes
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85642-7
- DISA-STIG-SLES-15-040230
- NIST-800-171-3.1.12
- NIST-800-53-AC-17(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-7(a)
- NIST-800-53-CM-7(b)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_disable_user_known_hosts
|
Disable X11 Forwarding
[ref]ruleThe X11Forwarding parameter provides the ability to tunnel X11 traffic
through the connection to enable remote graphic connections.
SSH has the capability to encrypt remote X11 connections when SSH's
X11Forwarding option is enabled.
To disable X11 Forwarding, add or correct the
following line in /etc/ssh/sshd_config :
X11Forwarding no Rationale:Disable X11 forwarding unless there is an operational requirement to use X11
applications directly. There is a small risk that the remote X11 servers of
users who are logged in via SSH with X11 forwarding could be compromised by
other users on the X11 server. Note that even if X11 forwarding is disabled,
users can always install their own forwarders. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*X11Forwarding\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "X11Forwarding no" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "X11Forwarding no" >> "/etc/ssh/sshd_config"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Disable X11 Forwarding
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*X11Forwarding\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*X11Forwarding\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*X11Forwarding\s+
line: X11Forwarding no
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85707-8
- DISA-STIG-SLES-15-040290
- NIST-800-53-CM-6.1(iv)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_disable_x11_forwarding
|
Do Not Allow SSH Environment Options
[ref]ruleTo ensure users are not able to override environment
variables of the SSH daemon, add or correct the following line
in /etc/ssh/sshd_config :
PermitUserEnvironment no Rationale:SSH environment options potentially allow users to bypass
access restriction in some configurations. Identifiers:
CCE-85666-6 References:
5.2.12, 11, 3, 9, 5.5.6, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.1.12, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, CM-6(b), CM-6.1(iv), PR.IP-1, SRG-OS-000480-GPOS-00229, SLES-15-040440, SV-235032r622137_rule, SRG-OS-000480-VMM-002000 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*PermitUserEnvironment\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "PermitUserEnvironment no" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "PermitUserEnvironment no" >> "/etc/ssh/sshd_config"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Do Not Allow SSH Environment Options
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*PermitUserEnvironment\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*PermitUserEnvironment\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*PermitUserEnvironment\s+
line: PermitUserEnvironment no
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85666-6
- CJIS-5.5.6
- DISA-STIG-SLES-15-040440
- NIST-800-171-3.1.12
- NIST-800-53-CM-6(b)
- NIST-800-53-CM-6.1(iv)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_do_not_permit_user_env
|
Enable Use of Strict Mode Checking
[ref]ruleSSHs StrictModes option checks file and ownership permissions in
the user's home directory .ssh folder before accepting login. If world-
writable permissions are found, logon is rejected. To enable StrictModes in SSH,
add or correct the following line in the /etc/ssh/sshd_config file:
StrictModes yes Rationale:If other users have access to modify user-specific SSH configuration files, they
may be able to log into the system as another user. Identifiers:
CCE-85645-0 References:
12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.1.12, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-3 R5.1.1, CIP-003-3 R5.3, CIP-004-3 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, AC-6, AC-17(a), CM-6(a), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, SLES-15-040260, SV-235010r622137_rule, SRG-OS-000480-VMM-002000 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*StrictModes\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "StrictModes yes" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "StrictModes yes" >> "/etc/ssh/sshd_config"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Enable Use of Strict Mode Checking
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*StrictModes\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*StrictModes\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*StrictModes\s+
line: StrictModes yes
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85645-0
- DISA-STIG-SLES-15-040260
- NIST-800-171-3.1.12
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-6
- NIST-800-53-CM-6(a)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_enable_strictmodes
|
Enable SSH Warning Banner
[ref]ruleTo enable the warning banner and ensure it is consistent
across the system, add or correct the following line in /etc/ssh/sshd_config :
Banner /etc/issue
Another section contains information on how to create an
appropriate system-wide warning banner.Rationale:The warning message reinforces policy awareness during the logon process and
facilitates possible legal action against attackers. Alternatively, systems
whose ownership should not be obvious should ensure usage of a banner that does
not provide easy attribution. Identifiers:
CCE-83263-4 References:
5.2.18, 1, 12, 15, 16, 5.5.6, DSS05.04, DSS05.10, DSS06.10, 3.1.9, CCI-000048, CCI-000050, CCI-001384, CCI-001385, CCI-001386, CCI-001387, CCI-001388, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, AC-8(a), AC-8(c), AC-17(a), CM-6(a), PR.AC-7, FTA_TAB.1, SRG-OS-000023-GPOS-00006, SRG-OS-000024-GPOS-00007, SRG-OS-000228-GPOS-00088, SLES-15-010040, SV-234805r622137_rule, SRG-OS-000023-VMM-000060, SRG-OS-000024-VMM-000070 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*Banner\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "Banner /etc/issue" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "Banner /etc/issue" >> "/etc/ssh/sshd_config"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Enable SSH Warning Banner
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*Banner\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*Banner\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*Banner\s+
line: Banner /etc/issue
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83263-4
- CJIS-5.5.6
- DISA-STIG-SLES-15-010040
- NIST-800-171-3.1.9
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-8(a)
- NIST-800-53-AC-8(c)
- NIST-800-53-CM-6(a)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_enable_warning_banner
|
Enable SSH Print Last Log
[ref]ruleWhen enabled, SSH will display the date and time of the last
successful account logon. To enable LastLog in
SSH, add or correct the following line in the /etc/ssh/sshd_config file:
PrintLastLog yes Rationale:Providing users feedback on when account accesses last occurred facilitates user
recognition and reporting of unauthorized account use. Identifiers:
CCE-85563-5 References:
1, 12, 15, 16, DSS05.04, DSS05.10, DSS06.10, CCI-000366, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, AC-9, AC-17(a), CM-6(a), PR.AC-7, SRG-OS-000480-GPOS-00227, SLES-15-020120, SV-234881r622137_rule Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*PrintLastLog\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "PrintLastLog yes" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "PrintLastLog yes" >> "/etc/ssh/sshd_config"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Enable SSH Print Last Log
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*PrintLastLog\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*PrintLastLog\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*PrintLastLog\s+
line: PrintLastLog yes
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85563-5
- DISA-STIG-SLES-15-020120
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-9
- NIST-800-53-CM-6(a)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_print_last_log
|
Set SSH Idle Timeout Interval
[ref]ruleSSH allows administrators to set an idle timeout interval. After this interval
has passed, the idle user will be automatically logged out.
To set an idle timeout interval, edit the following line in /etc/ssh/sshd_config as
follows:
ClientAliveInterval 600
The timeout interval is given in seconds. For example, have a timeout
of 10 minutes, set interval to 600.
If a shorter timeout has already been set for the login shell, that value will
preempt any SSH setting made in /etc/ssh/sshd_config . Keep in mind that
some processes may stop SSH from correctly detecting that the user is idle.Warning:
SSH disconnecting idle clients will not have desired effect without also
configuring ClientAliveCountMax in the SSH service configuration. Warning:
Following conditions may prevent the SSH session to time out:
- Remote processes on the remote machine generates output. As the output has to be transferred over the network to the client, the timeout is reset every time such transfer happens.
- Any
scp or sftp activity by the same user to the host resets the timeout.
Rationale:Terminating an idle ssh session within a short time period reduces the window of
opportunity for unauthorized personnel to take control of a management session
enabled on the console or console port that has been let unattended. Identifiers:
CCE-83281-6 References:
BP28(R29), 5.2.16, 1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8, 5.5.6, APO13.01, BAI03.01, BAI03.02, BAI03.03, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.1.11, CCI-000879, CCI-001133, CCI-002361, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2, A.12.4.1, A.12.4.3, A.14.1.1, A.14.2.1, A.14.2.5, A.18.1.4, A.6.1.2, A.6.1.5, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-3 R2.2.3, CIP-007-3 R5.1, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, CM-6(a), AC-17(a), AC-2(5), AC-12, AC-17(a), SC-10, CM-6(a), DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.IP-2, Req-8.1.8, SRG-OS-000126-GPOS-00066, SRG-OS-000163-GPOS-00072, SRG-OS-000279-GPOS-00109, SRG-OS-000395-GPOS-00175, SLES-15-010280, SV-234827r622137_rule, SRG-OS-000480-VMM-002000 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
sshd_idle_timeout_value="600"
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*ClientAliveInterval\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "ClientAliveInterval $sshd_idle_timeout_value" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "ClientAliveInterval $sshd_idle_timeout_value" >> "/etc/ssh/sshd_config"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: XCCDF Value sshd_idle_timeout_value # promote to variable
set_fact:
sshd_idle_timeout_value: !!str 600
tags:
- always
- name: Set SSH Idle Timeout Interval
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*ClientAliveInterval\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*ClientAliveInterval\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*ClientAliveInterval\s+
line: ClientAliveInterval {{ sshd_idle_timeout_value }}
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83281-6
- CJIS-5.5.6
- DISA-STIG-SLES-15-010280
- NIST-800-171-3.1.11
- NIST-800-53-AC-12
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-2(5)
- NIST-800-53-CM-6(a)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-10
- PCI-DSS-Req-8.1.8
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_set_idle_timeout
|
Set SSH Client Alive Count Max to zero
[ref]ruleThe SSH server sends at most ClientAliveCountMax messages
during a SSH session and waits for a response from the SSH client.
The option ClientAliveInterval configures timeout after
each ClientAliveCountMax message. If the SSH server does not
receive a response from the client, then the connection is considered idle
and terminated.
To ensure the SSH idle timeout occurs precisely when the
ClientAliveInterval is set, set the ClientAliveCountMax to
value of 0 . Rationale:This ensures a user login will be terminated as soon as the ClientAliveInterval
is reached. Identifiers:
CCE-83284-0 References:
1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8, 5.5.6, APO13.01, BAI03.01, BAI03.02, BAI03.03, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.1.11, CCI-000879, CCI-001133, CCI-002361, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2, A.12.4.1, A.12.4.3, A.14.1.1, A.14.2.1, A.14.2.5, A.18.1.4, A.6.1.2, A.6.1.5, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-3 R2.2.3, CIP-007-3 R5.1, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, AC-2(5), AC-12, AC-17(a), SC-10, CM-6(a), DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.IP-2, Req-8.1.8, SRG-OS-000163-GPOS-00072, SRG-OS-000279-GPOS-00109, SLES-15-010320, SV-234830r622137_rule, SRG-OS-000480-VMM-002000 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*ClientAliveCountMax\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "ClientAliveCountMax 0" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "ClientAliveCountMax 0" >> "/etc/ssh/sshd_config"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Set SSH Client Alive Count Max to zero
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*ClientAliveCountMax\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*ClientAliveCountMax\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*ClientAliveCountMax\s+
line: ClientAliveCountMax 0
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83284-0
- CJIS-5.5.6
- DISA-STIG-SLES-15-010320
- NIST-800-171-3.1.11
- NIST-800-53-AC-12
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-2(5)
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-10
- PCI-DSS-Req-8.1.8
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_set_keepalive_0
|
Set SSH Daemon LogLevel to VERBOSE
[ref]ruleThe VERBOSE parameter configures the SSH daemon to record login and logout activity.
To specify the log level in
SSH, add or correct the following line in the /etc/ssh/sshd_config file:
LogLevel VERBOSE Rationale:SSH provides several logging levels with varying amounts of verbosity. DEBUG is specifically
not recommended other than strictly for debugging SSH communications since it provides
so much data that it is difficult to identify important security information. INFO or
VERBOSE level is the basic level that only records login activity of SSH users. In many
situations, such as Incident Response, it is important to determine when a particular user was active
on a system. The logout record can eliminate those users who disconnected, which helps narrow the
field. Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if [ -e "/etc/ssh/sshd_config" ] ; then
LC_ALL=C sed -i "/^\s*LogLevel\s\+/Id" "/etc/ssh/sshd_config"
else
touch "/etc/ssh/sshd_config"
fi
cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert before the line matching the regex '^Match'.
line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
# There was no match of '^Match', insert at
# the end of the file.
printf '%s\n' "LogLevel VERBOSE" >> "/etc/ssh/sshd_config"
else
head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
printf '%s\n' "LogLevel VERBOSE" >> "/etc/ssh/sshd_config"
tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
fi
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Set SSH Daemon LogLevel to VERBOSE
block:
- name: Check for duplicate values
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*LogLevel\s+
state: absent
check_mode: true
changed_when: false
register: dupes
- name: Deduplicate values from /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: false
regexp: (?i)^\s*LogLevel\s+
state: absent
when: dupes.found is defined and dupes.found > 1
- name: Insert correct line to /etc/ssh/sshd_config
lineinfile:
path: /etc/ssh/sshd_config
create: true
regexp: (?i)^\s*LogLevel\s+
line: LogLevel VERBOSE
state: present
insertbefore: ^[#\s]*Match
validate: /usr/sbin/sshd -t -f %s
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83270-9
- DISA-STIG-SLES-15-010150
- NIST-800-53-AC-17(1)
- NIST-800-53-AC-17(a)
- NIST-800-53-CM-6(a)
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_set_loglevel_verbose
|
Use Only FIPS 140-2 Validated Ciphers
[ref]ruleLimit the ciphers to those algorithms which are FIPS-approved.
The following line in /etc/ssh/sshd_config
demonstrates use of FIPS-approved ciphers:
Ciphers aes256-ctr,aes192-ctr,aes128-ctr
This rule ensures that there are configured ciphers mentioned
above (or their subset), keeping the given order of algorithms.Warning:
The system needs to be rebooted for these changes to take effect. Warning:
System Crypto Modules must be provided by a vendor that undergoes
FIPS-140 certifications.
FIPS-140 is applicable to all Federal agencies that use
cryptographic-based security systems to protect sensitive information
in computer and telecommunication systems (including voice systems) as
defined in Section 5131 of the Information Technology Management Reform
Act of 1996, Public Law 104-106. This standard shall be used in
designing and implementing cryptographic modules that Federal
departments and agencies operate or are operated for them under
contract. See https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.140-2.pdf
To meet this, the system has to have cryptographic software provided by
a vendor that has undergone this certification. This means providing
documentation, test results, design information, and independent third
party review by an accredited lab. While open source software is
capable of meeting this, it does not meet FIPS-140 unless the vendor
submits to this process. Rationale:Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and therefore
cannot be relied upon to provide confidentiality or integrity, and system data may be compromised.
Operating systems utilizing encryption are required to use FIPS-compliant mechanisms for authenticating to
cryptographic modules.
FIPS 140-2 is the current standard for validating that mechanisms used to access cryptographic modules
utilize authentication that meets industry and government requirements. For government systems, this allows
Security Levels 1, 2, 3, or 4 for use on SUSE Linux Enterprise 15. Identifiers:
CCE-83271-7 References:
CCI-000068, CCI-000366, CCI-000803, CCI-000877, CCI-002890, CCI-003123, SRG-OS-000033-GPOS-00014, SRG-OS-000120-GPOS-00061, SRG-OS-000125-GPOS-00065, SRG-OS-000250-GPOS-00093, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174, SLES-15-010160, SV-234816r622137_rule Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if grep -q -P '^\s*[Cc]iphers\s+' /etc/ssh/sshd_config; then
sed -i 's/^\s*[Cc]iphers.*/Ciphers aes256-ctr,aes192-ctr,aes128-ctr/' /etc/ssh/sshd_config
else
echo "Ciphers aes256-ctr,aes192-ctr,aes128-ctr" >> /etc/ssh/sshd_config
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Configure sshd to use approved ciphers
lineinfile:
path: /etc/ssh/sshd_config
line: Ciphers aes256-ctr,aes192-ctr,aes128-ctr
state: present
regexp: ^[\s]*[Cc]iphers[\s]+(aes256-ctr(?=[\w,-@]+|$),?)?(aes192-ctr(?=[\w,-@]+|$),?)?(aes128-ctr(?=[\w,-@]+|$),?)?[\s]*(?:#.*)?$
create: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83271-7
- DISA-STIG-SLES-15-010160
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_use_approved_ciphers_ordered_stig
|
Use Only FIPS 140-2 Validated MACs
[ref]ruleLimit the MACs to those hash algorithms which are FIPS-approved.
The following line in /etc/ssh/sshd_config
demonstrates use of FIPS-approved MACs:
MACs hmac-sha2-512,hmac-sha2-256
This rule ensures that there are configured MACs mentioned
above (or their subset), keeping the given order of algorithms.Warning:
The system needs to be rebooted for these changes to take effect. Warning:
System Crypto Modules must be provided by a vendor that undergoes
FIPS-140 certifications.
FIPS-140 is applicable to all Federal agencies that use
cryptographic-based security systems to protect sensitive information
in computer and telecommunication systems (including voice systems) as
defined in Section 5131 of the Information Technology Management Reform
Act of 1996, Public Law 104-106. This standard shall be used in
designing and implementing cryptographic modules that Federal
departments and agencies operate or are operated for them under
contract. See https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.140-2.pdf
To meet this, the system has to have cryptographic software provided by
a vendor that has undergone this certification. This means providing
documentation, test results, design information, and independent third
party review by an accredited lab. While open source software is
capable of meeting this, it does not meet FIPS-140 unless the vendor
submits to this process. Rationale:DoD Information Systems are required to use FIPS-approved cryptographic hash
functions. The only SSHv2 hash algorithms meeting this requirement is SHA2. Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
if grep -q -P '^\s*MACs\s+' /etc/ssh/sshd_config; then
sed -i 's/^\s*MACs.*/MACs hmac-sha2-512,hmac-sha2-256/' /etc/ssh/sshd_config
else
echo "MACs hmac-sha2-512,hmac-sha2-256" >> /etc/ssh/sshd_config
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | restrict |
---|
- name: Configure sshd to use approved MACs
lineinfile:
path: /etc/ssh/sshd_config
line: MACs hmac-sha2-512,hmac-sha2-256
state: present
regexp: ^[\s]*MACs[\s]+(hmac-sha2-512(?=[\w,-@]+|$),?)?(hmac-sha2-256(?=[\w,-@]+|$),?)?[\s]*(?:#.*)?$
create: true
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83280-8
- DISA-STIG-SLES-15-010270
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- restrict_strategy
- sshd_use_approved_macs_ordered_stig
|
Enable the OpenSSH Service
[ref]ruleThe SSH server service, sshd, is commonly needed.
The sshd service can be enabled with the following command:
$ sudo systemctl enable sshd.service Rationale:Without protection of the transmitted information, confidentiality, and
integrity may be compromised because unprotected communications can be
intercepted and either read or altered.
This checklist item applies to both internal and external networks and all types
of information system components from which information can be transmitted (e.g., servers,
mobile devices, notebook computers, printers, copiers, scanners, etc). Communication paths
outside the physical protection of a controlled boundary are exposed to the possibility
of interception and modification. Identifiers:
CCE-83297-2 References:
13, 14, APO01.06, DSS05.02, DSS05.04, DSS05.07, DSS06.02, DSS06.06, 3.1.13, 3.5.4, 3.13.8, CCI-002418, CCI-002420, CCI-002421, CCI-002422, SR 3.1, SR 3.8, SR 4.1, SR 4.2, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), SC-8, SC-8(1), SC-8(2), SC-8(3), SC-8(4), PR.DS-2, PR.DS-5, SRG-OS-000423-GPOS-00187, SRG-OS-000423-GPOS-00188, SRG-OS-000423-GPOS-00189, SRG-OS-000423-GPOS-00190, SLES-15-010530, SV-234860r622137_rule Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" unmask 'sshd.service'
"$SYSTEMCTL_EXEC" start 'sshd.service'
"$SYSTEMCTL_EXEC" enable 'sshd.service'
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
- name: Enable service sshd
block:
- name: Gather the package facts
package_facts:
manager: auto
- name: Enable service sshd
service:
name: sshd
enabled: 'yes'
state: started
masked: 'no'
when:
- '"openssh" in ansible_facts.packages'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83297-2
- DISA-STIG-SLES-15-010530
- NIST-800-171-3.1.13
- NIST-800-171-3.13.8
- NIST-800-171-3.5.4
- NIST-800-53-CM-6(a)
- NIST-800-53-SC-8
- NIST-800-53-SC-8(1)
- NIST-800-53-SC-8(2)
- NIST-800-53-SC-8(3)
- NIST-800-53-SC-8(4)
- enable_strategy
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- service_sshd_enabled
Remediation Puppet snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | enable |
---|
include enable_sshd
class enable_sshd {
service {'sshd':
enable => true,
ensure => 'running',
}
}
|
Verify Permissions on SSH Server Private *_key Key Files
[ref]rule
To properly set the permissions of /etc/ssh/*_key , run the command:
$ sudo chmod 0600 /etc/ssh/*_key Rationale:If an unauthorized user obtains the private SSH host key file, the host could be
impersonated. Identifiers:
CCE-85644-3 References:
BP28(R36), 5.2.2, 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.1.13, 3.13.10, CCI-000366, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-3 R5.1.1, CIP-003-3 R5.3, CIP-004-3 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, AC-17(a), CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, SLES-15-040250, SV-235009r622137_rule Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
readarray -t files < <(find /etc/ssh/)
for file in "${files[@]}"; do
if basename $file | grep -q '^.*_key$'; then
chmod 0600 $file
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | configure |
---|
- name: Find /etc/ssh/ file(s)
find:
paths: /etc/ssh/
patterns: ^.*_key$
use_regex: true
register: files_found
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85644-3
- DISA-STIG-SLES-15-040250
- NIST-800-171-3.1.13
- NIST-800-171-3.13.10
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_sshd_private_key
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set permissions for /etc/ssh/ file(s)
file:
path: '{{ item.path }}'
mode: '0600'
with_items:
- '{{ files_found.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85644-3
- DISA-STIG-SLES-15-040250
- NIST-800-171-3.1.13
- NIST-800-171-3.13.10
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_sshd_private_key
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Puppet snippet: (show)
include ssh_private_key_perms
class ssh_private_key_perms {
exec { 'sshd_priv_key':
command => "chmod 0640 /etc/ssh/*_key",
path => '/bin:/usr/bin'
}
}
|
Verify Permissions on SSH Server Public *.pub Key Files
[ref]rule To properly set the permissions of /etc/ssh/*.pub , run the command: $ sudo chmod 0644 /etc/ssh/*.pub Rationale:If a public host key file is modified by an unauthorized user, the SSH service
may be compromised. Identifiers:
CCE-85643-5 References:
5.2.3, 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.1.13, 3.13.10, CCI-000366, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-3 R5.1.1, CIP-003-3 R5.3, CIP-004-3 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, AC-17(a), CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, SLES-15-040240, SV-235008r622137_rule Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then
readarray -t files < <(find /etc/ssh/)
for file in "${files[@]}"; do
if basename $file | grep -q '^.*.pub$'; then
chmod 0644 $file
fi
done
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | low |
---|
Strategy: | configure |
---|
- name: Find /etc/ssh/ file(s)
find:
paths: /etc/ssh/
patterns: ^.*.pub$
use_regex: true
register: files_found
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85643-5
- DISA-STIG-SLES-15-040240
- NIST-800-171-3.1.13
- NIST-800-171-3.13.10
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_sshd_pub_key
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Set permissions for /etc/ssh/ file(s)
file:
path: '{{ item.path }}'
mode: '0644'
with_items:
- '{{ files_found.files }}'
when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-85643-5
- DISA-STIG-SLES-15-040240
- NIST-800-171-3.1.13
- NIST-800-171-3.13.10
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- configure_strategy
- file_permissions_sshd_pub_key
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
Remediation Puppet snippet: (show)
include ssh_public_key_perms
class ssh_public_key_perms {
exec { 'sshd_pub_key':
command => "chmod 0644 /etc/ssh/*.pub",
path => '/bin:/usr/bin'
}
}
|
System Security Services Daemon
[ref]groupThe System Security Services Daemon (SSSD) is a system daemon that provides access
to different identity and authentication providers such as Red Hat's IdM, Microsoft's AD,
openLDAP, MIT Kerberos, etc. It uses a common framework that can provide caching and offline
support to systems utilizing SSSD. SSSD using caching to reduce load on authentication
servers permit offline authentication as well as store extended user data.
For more information, see |
contains 2 rules |
Configure SSSD's Memory Cache to Expire
[ref]ruleSSSD's memory cache should be configured to set to expire records after
86400 seconds.
To configure SSSD to expire memory cache, set memcache_timeout to
86400 under the
[nss] section in /etc/sssd/sssd.conf .
For example:
[nss]
memcache_timeout = 86400
Rationale:If cached authentication information is out-of-date, the validity of the
authentication information may be questionable. Identifiers:
CCE-83295-6 References:
1, 12, 15, 16, 5, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, CCI-002007, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, CM-6(a), IA-5(13), PR.AC-1, PR.AC-6, PR.AC-7, SRG-OS-000383-GPOS-00166, SLES-15-010490, SV-234857r622137_rule, SRG-OS-000383-VMM-001570 Remediation Shell script: (show)
# Remediation is applicable only in certain platforms
if rpm --quiet -q sssd && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
var_sssd_memcache_timeout="86400"
SSSD_CONF="/etc/sssd/sssd.conf"
MEMCACHE_TIMEOUT_REGEX="[[:space:]]*\[nss]([^\n\[]*\n+)+?[[:space:]]*memcache_timeout"
NSS_REGEX="[[:space:]]*\[nss]"
# Try find [nss] and memcache_timeout in sssd.conf, if it exists, set to
# var_sssd_memcache_timeout, if it isn't here, add it, if [nss] doesn't
# exist, add it there
if grep -qzosP $MEMCACHE_TIMEOUT_REGEX $SSSD_CONF; then
sed -i "s/memcache_timeout[^(\n)]*/memcache_timeout = $var_sssd_memcache_timeout/" $SSSD_CONF
elif grep -qs $NSS_REGEX $SSSD_CONF; then
sed -i "/$NSS_REGEX/a memcache_timeout = $var_sssd_memcache_timeout" $SSSD_CONF
else
mkdir -p /etc/sssd
touch $SSSD_CONF
echo -e "[nss]\nmemcache_timeout = $var_sssd_memcache_timeout" >> $SSSD_CONF
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83295-6
- DISA-STIG-SLES-15-010490
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(13)
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- sssd_memcache_timeout
- unknown_strategy
- name: XCCDF Value var_sssd_memcache_timeout # promote to variable
set_fact:
var_sssd_memcache_timeout: !!str 86400
tags:
- always
- name: Test for domain group
command: grep '\s*\[domain\/[^]]*]' /etc/sssd/sssd.conf
register: test_grep_domain
ignore_errors: true
changed_when: false
check_mode: false
when:
- '"sssd" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83295-6
- DISA-STIG-SLES-15-010490
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(13)
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- sssd_memcache_timeout
- unknown_strategy
- name: Add default domain group (if no domain there)
ini_file:
path: /etc/sssd/sssd.conf
section: '{{ item.section }}'
option: '{{ item.option }}'
value: '{{ item.value }}'
create: true
mode: 384
with_items:
- section: sssd
option: domains
value: default
- section: domain/default
option: id_provider
value: files
when:
- '"sssd" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- test_grep_domain.stdout is defined
- test_grep_domain.stdout | length < 1
tags:
- CCE-83295-6
- DISA-STIG-SLES-15-010490
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(13)
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- sssd_memcache_timeout
- unknown_strategy
- name: Configure SSSD's Memory Cache to Expire
ini_file:
dest: /etc/sssd/sssd.conf
section: nss
option: memcache_timeout
value: '{{ var_sssd_memcache_timeout }}'
create: true
mode: 384
when:
- '"sssd" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83295-6
- DISA-STIG-SLES-15-010490
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(13)
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- sssd_memcache_timeout
- unknown_strategy
|
Configure SSSD to Expire Offline Credentials
[ref]ruleSSSD should be configured to expire offline credentials after 1 day.
To configure SSSD to expire offline credentials, set
offline_credentials_expiration to 1 under the [pam]
section in /etc/sssd/sssd.conf . For example:
[pam]
offline_credentials_expiration = 1
Rationale:If cached authentication information is out-of-date, the validity of the
authentication information may be questionable. Identifiers:
CCE-83296-4 References:
1, 12, 15, 16, 5, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, CCI-002007, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, CM-6(a), IA-5(13), PR.AC-1, PR.AC-6, PR.AC-7, SRG-OS-000383-GPOS-00166, SLES-15-010500, SV-234858r622137_rule, SRG-OS-000383-VMM-001570 Remediation Shell script: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Strategy: | configure |
---|
# Remediation is applicable only in certain platforms
if rpm --quiet -q sssd && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then
SSSD_CONF="/etc/sssd/sssd.conf"
SSSD_OPT="offline_credentials_expiration"
SSSD_OPT_VAL=1
PAM_REGEX="[[:space:]]*\[pam]"
PAM_OPT_REGEX="${PAM_REGEX}([^\n\[]*\n+)+?[[:space:]]*${SSSD_OPT}"
# Try find [pam] and offline_credentials_expiration in sssd.conf, if it exists
# set it to 1, if it doesn't exist add it, if [pam] section doesn't exist add
# the section and the configuration option.
if grep -qzosP $PAM_OPT_REGEX $SSSD_CONF; then
sed -i "s/${SSSD_OPT}[^(\n)]*/${SSSD_OPT} = ${SSSD_OPT_VAL}/" $SSSD_CONF
elif grep -qs $PAM_REGEX $SSSD_CONF; then
sed -i "/$PAM_REGEX/a ${SSSD_OPT} = ${SSSD_OPT_VAL}" $SSSD_CONF
else
mkdir -p /etc/sssd
touch $SSSD_CONF
echo -e "[pam]\n${SSSD_OPT} = ${SSSD_OPT_VAL}" >> $SSSD_CONF
fi
else
>&2 echo 'Remediation is not applicable, nothing was done'
fi
Remediation Ansible snippet: (show)
Complexity: | low |
---|
Disruption: | medium |
---|
Strategy: | configure |
---|
- name: Gather the package facts
package_facts:
manager: auto
tags:
- CCE-83296-4
- DISA-STIG-SLES-15-010500
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(13)
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- sssd_offline_cred_expiration
- name: Test for domain group
command: grep '\s*\[domain\/[^]]*]' /etc/sssd/sssd.conf
register: test_grep_domain
ignore_errors: true
changed_when: false
check_mode: false
when:
- '"sssd" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83296-4
- DISA-STIG-SLES-15-010500
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(13)
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- sssd_offline_cred_expiration
- name: Add default domain group (if no domain there)
ini_file:
path: /etc/sssd/sssd.conf
section: '{{ item.section }}'
option: '{{ item.option }}'
value: '{{ item.value }}'
create: true
mode: 384
with_items:
- section: sssd
option: domains
value: default
- section: domain/default
option: id_provider
value: files
when:
- '"sssd" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
- test_grep_domain.stdout is defined
- test_grep_domain.stdout | length < 1
tags:
- CCE-83296-4
- DISA-STIG-SLES-15-010500
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(13)
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- sssd_offline_cred_expiration
- name: Configure SSD to Expire Offline Credentials
ini_file:
dest: /etc/sssd/sssd.conf
section: pam
option: offline_credentials_expiration
value: 1
create: true
mode: 384
when:
- '"sssd" in ansible_facts.packages'
- ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- CCE-83296-4
- DISA-STIG-SLES-15-010500
- NIST-800-53-CM-6(a)
- NIST-800-53-IA-5(13)
- configure_strategy
- low_complexity
- medium_disruption
- medium_severity
- no_reboot_needed
- sssd_offline_cred_expiration
|