Configure auditd admin_space_left Action on Low Disk Space

An XCCDF Rule

Description

The 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:

admin_space_left_action = ACTION

Set this value to single to cause the system to switch to single user mode for corrective action. Acceptable values also include suspend 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

Administrators should be made aware of an inability to record audit records. If a separate partition or logical volume of adequate size is used, running low on space for audit records should never occur.

ID: xccdf_org.ssgproject.content_rule_auditd_data_retention_admin_space_left_action
Severity: Medium
References: 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-000140 CCI-001343 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

AU-5(1) AU-5(2) AU-5(4) AU-5(b) CM-6(a)

DE.AE-3 DE.AE-5 PR.DS-4 PR.PT-1 RS.AN-1 RS.AN-4

Req-10.7

10.5.1

SRG-OS-000343-GPOS-00134

4.1.2.3

CCE-91618-9
Updated: about 1 year ago

# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

var_auditd_admin_space_left_action='<xccdf-1.2:sub xmlns:xccdf-1.2="http://checklists.nist.gov/xccdf/1.2" idref="xccdf_org.ssgproject.content_value_var_auditd_admin_space_left_action" use="legacy"/>'

var_auditd_admin_space_left_action="$(echo $var_auditd_admin_space_left_action | cut -d \| -f 1)"

AUDITCONFIG=/etc/audit/auditd.conf

# 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' <<< "^admin_space_left_action")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_auditd_admin_space_left_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 "^admin_space_left_action\\>" "$AUDITCONFIG"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^admin_space_left_action\\>.*/$escaped_formatted_output/gi" "$AUDITCONFIG"
else
    if [[ -s "$AUDITCONFIG" ]] && [[ -n "$(tail -c 1 -- "$AUDITCONFIG" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "$AUDITCONFIG"
    fi
    cce="CCE-91618-9"
    printf '# 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

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CCE-91618-9
  - CJIS-5.4.1.1  - NIST-800-171-3.3.1
  - 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
  - PCI-DSSv4-10.5.1
  - auditd_data_retention_admin_space_left_action
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_auditd_admin_space_left_action # promote to variable
  set_fact:
    var_auditd_admin_space_left_action: !!str <xccdf-1.2:sub xmlns:xccdf-1.2="http://checklists.nist.gov/xccdf/1.2" idref="xccdf_org.ssgproject.content_value_var_auditd_admin_space_left_action" use="legacy"/>
  tags:
    - always

- name: Configure auditd admin_space_left Action on Low Disk Space
  lineinfile:
    dest: /etc/audit/auditd.conf
    line: admin_space_left_action = {{ var_auditd_admin_space_left_action .split('|')[0]
      }}
    regexp: ^\s*admin_space_left_action\s*=\s*.*$
    state: present
    create: true
  when:
  - '"audit" in ansible_facts.packages'
  - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
  tags:
  - CCE-91618-9
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - 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
  - PCI-DSSv4-10.5.1
  - auditd_data_retention_admin_space_left_action
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Configure auditd admin_space_left Action on Low Disk Space

Description

Rationale

Remediation - Shell Script

Remediation - Ansible