Configure auditd Number of Logs Retained

An XCCDF Rule

Description

Determine how many log files auditd should retain when it rotates logs. Edit the file /etc/audit/auditd.conf. Add or modify the following line, substituting NUMLOGS with the correct value of :

num_logs = NUMLOGS

Set the value to 5 for general-purpose systems. Note that values less than 2 result in no log rotation.

Rationale

The total storage for audit log files must be large enough to retain log information over the period required. This is a function of the maximum log file size and the number of logs retained.

ID: xccdf_org.ssgproject.content_rule_auditd_data_retention_num_logs
Severity: Medium
References: 1 11 12 13 14 15 16 19 3 4 5 6 7 8

5.4.1.1

APO11.04 APO12.06 BAI03.05 BAI08.02 DSS02.02 DSS02.04 DSS02.07 DSS03.01 DSS05.04 DSS05.07 MEA02.01

3.3.1

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

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

CIP-004-6 R2.2.3 CIP-004-6 R3.3 CIP-007-3 R5.2 CIP-007-3 R5.3.1 CIP-007-3 R5.3.2 CIP-007-3 R5.3.3 CIP-007-3 R6.5

AU-11 CM-6(a)

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

Req-10.7

CCE-83688-2
Updated: about 1 year ago

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CCE-83688-2
  - CJIS-5.4.1.1  - NIST-800-171-3.3.1
  - NIST-800-53-AU-11
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.7
  - auditd_data_retention_num_logs
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_auditd_num_logs # promote to variable
  set_fact:
    var_auditd_num_logs: !!str <xccdf-1.2:sub xmlns:xccdf-1.2="http://checklists.nist.gov/xccdf/1.2" idref="xccdf_org.ssgproject.content_value_var_auditd_num_logs" use="legacy"/>
  tags:
    - always

- name: Configure auditd Number of Logs Retained
  lineinfile:
    dest: /etc/audit/auditd.conf
    line: num_logs = {{ var_auditd_num_logs }}
    regexp: ^\s*num_logs\s*=\s*.*$
    state: present
    create: true
  when:
  - '"audit" in ansible_facts.packages'
  - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
  tags:
  - CCE-83688-2
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-53-AU-11
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.7
  - auditd_data_retention_num_logs
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

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

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

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' <<< "^num_logs")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_auditd_num_logs"

# 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 "^num_logs\\>" "$AUDITCONFIG"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^num_logs\\>.*/$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-83688-2"
    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

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,{{ %23%0A%23%20This%20file%20controls%20the%20configuration%20of%20the%20audit%20daemon%0A%23%0A%0Alocal_events%20%3D%20yes%0Awrite_logs%20%3D%20yes%0Alog_file%20%3D%20/var/log/audit/audit.log%0Alog_group%20%3D%20root%0Alog_format%20%3D%20ENRICHED%0Aflush%20%3D%20%7B%7B.var_auditd_flush%7D%7D%0Afreq%20%3D%2050%0Amax_log_file%20%3D%20%7B%7B.var_auditd_max_log_file%7D%7D%0Anum_logs%20%3D%20%7B%7B.var_auditd_num_logs%7D%7D%0Apriority_boost%20%3D%204%0Aname_format%20%3D%20hostname%0A%23%23name%20%3D%20mydomain%0Amax_log_file_action%20%3D%20%7B%7B.var_auditd_max_log_file_action%7D%7D%0Aspace_left%20%3D%20%7B%7B.var_auditd_space_left%7D%7D%0Aspace_left_action%20%3D%20%7B%7B.var_auditd_space_left_action%7D%7D%0Averify_email%20%3D%20yes%0Aaction_mail_acct%20%3D%20%7B%7B.var_auditd_action_mail_acct%7D%7D%0Aadmin_space_left%20%3D%2050%0Aadmin_space_left_action%20%3D%20syslog%0Adisk_full_action%20%3D%20%7B%7B.var_auditd_disk_full_action%7D%7D%0Adisk_error_action%20%3D%20%7B%7B.var_auditd_disk_error_action%7D%7D%0Ause_libwrap%20%3D%20yes%0A%23%23tcp_listen_port%20%3D%2060%0Atcp_listen_queue%20%3D%205%0Atcp_max_per_addr%20%3D%201%0A%23%23tcp_client_ports%20%3D%201024-65535%0Atcp_client_max_idle%20%3D%200%0Atransport%20%3D%20TCP%0Akrb5_principal%20%3D%20auditd%0A%23%23krb5_key_file%20%3D%20/etc/audit/audit.key%0Adistribute_network%20%3D%20no%0Aq_depth%20%3D%20400%0Aoverflow_action%20%3D%20syslog%0Amax_restarts%20%3D%2010%0Aplugin_dir%20%3D%20/etc/audit/plugins.d }}
        mode: 0640
        path: /etc/audit/auditd.conf
        overwrite: true

Configure auditd Number of Logs Retained

Description

Rationale

Remediation - Ansible

Remediation - Shell Script

Remediation - Kubernetes Patch