Set number of records to cause an explicit flush to audit logs

An XCCDF Rule

Description

To configure Audit daemon to issue an explicit flush to disk command after writing records, set freq to in /etc/audit/auditd.conf.

Rationale

If option freq isn't set to , the flush to disk may happen after higher number of records, increasing the danger of audit loss.

ID: xccdf_org.ssgproject.content_rule_auditd_freq
Severity: Medium
References: CM-6

FAU_GEN.1

SRG-OS-000051-GPOS-00024
Updated: about 1 year ago

# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && dpkg-query --show --showformat='${db:Status-Status}\n' 'auditd' 2>/dev/null | grep -q installed; then

if [ -e "/etc/audit/auditd.conf" ] ; then
    
    LC_ALL=C sed -i "/^\s*freq\s*=\s*/Id" "/etc/audit/auditd.conf"else
    touch "/etc/audit/auditd.conf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/audit/auditd.conf"

cp "/etc/audit/auditd.conf" "/etc/audit/auditd.conf.bak"
# Insert at the end of the file
printf '%s\n' "freq = 50" >> "/etc/audit/auditd.conf"
# Clean up after ourselves.
rm "/etc/audit/auditd.conf.bak"

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6
  - auditd_freq  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Set number of records to cause an explicit flush to audit logs
  block:

  - name: Check for duplicate values
    lineinfile:
      path: /etc/audit/auditd.conf
      create: true
      regexp: (?i)^\s*freq\s*=\s*
      state: absent
    check_mode: true
    changed_when: false
    register: dupes

  - name: Deduplicate values from /etc/audit/auditd.conf
    lineinfile:
      path: /etc/audit/auditd.conf
      create: true
      regexp: (?i)^\s*freq\s*=\s*
      state: absent
    when: dupes.found is defined and dupes.found > 1

  - name: Insert correct line to /etc/audit/auditd.conf
    lineinfile:
      path: /etc/audit/auditd.conf
      create: true
      regexp: (?i)^\s*freq\s*=\s*
      line: freq = 50
      state: present
  when:
  - '"auditd" in ansible_facts.packages'
  - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
  tags:
  - NIST-800-53-CM-6
  - auditd_freq
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Set number of records to cause an explicit flush to audit logs

Description

Rationale

Remediation - Shell Script

Remediation - Ansible