SV-238317r991581: The Ubuntu operating system must generate audit records for the /var/log/btmp file. | Canonical Ubuntu 20.04 LTS STIG SCAP Benchmark

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Assessment Title

Rule Text

The Ubuntu operating system must generate audit records for the /var/log/btmp file.

Description

Discussion Text

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).

How this relates to the STIG checklist: STIG vs SCAP benchmark.

IA Controls

NIST SP 800-53

Not mappedCCI-000172

References

DPMS Target Canonical Ubuntu 20.04 LTS DISA DPMS Target Canonical Ubuntu 20.04 LTS 5318

SCC Automation Reference

The reconstructed evaluation script behind this rule's OVAL check(s) — every module a compound check combines, with this rule's own concrete values and DISA's SCC tool's real per-module mechanism curated from static teardown of SCC releases.

#!/bin/bash
# Reconstructed from oval:mil.disa.stig.ubuntu2004:def:199
# The Ubuntu operating system must generate audit records for the /var/log/btmp file.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# textfilecontent54_object (textfilecontent54_test)
test_1() {
  grep -Pq '^\s*-w\s+/var/log/btmp(?:\s+-p\s+(?:[rx]*w[rx]*a[rx]*|[rx]*a[rx]*w[rx]*))?(?:\s+(?:-k\s+|-F\s+key=)\S+)*\s*$' '/etc/audit/audit.rules' &>/dev/null
}
# textfilecontent54_object (textfilecontent54_test)
test_2() {
  grep -Pq '^\s*-a\s+(?:always,exit|exit,always)\s+-F\s+path=/var/log/btmp\s+-F\s+perm=(?:[rx]*w[rx]*a[rx]*|[rx]*a[rx]*w[rx]*)(?:\s+(?:-k\s+|-F\s+key=)\S+)*\s*$' '/etc/audit/audit.rules' &>/dev/null
}

if ( test_1 || test_2 ); then
  echo "PASS"
else
  echo "FAIL"
fi

Assessment Script Powered by AISandbox-executed

A standalone Shell script to assess this control automatically. Review before running it in your environment.

Syntax-checked and actually executed in an isolated sandbox (not the real system this checks) — confirmed to run without errors.

#!/bin/sh
# DISA STIG / SCAP compliance check for Ubuntu generating audit records for /var/log/btmp file
if [ -f "/etc/audit/rules.d/stig.rules" ]; then
    grep '^\s*-w\s+/var/log/btmp\s+-p\s+wa\s*-\s*k\s+logins' /etc/audit/rules.d/stig.rules | grep -q. && echo "PASS" && exit 0 || echo "FAIL" && exit 1
else
    echo "FAIL" && exit 1
fi

Remediation

Configure the audit system to generate audit events showing start and stop times for user access via the "/var/log/btmp file". 
 
Add or update the following rules in the "/etc/audit/rules.d/stig.rules" file: 
 
-w /var/log/btmp -p wa -k logins 
  
To reload the rules file, issue the following command: 
 
$ sudo augenrules --load