SV-258054r958736: RHEL 9 must automatically lock an account when three unsuccessful logon attempts occur. | Red Hat Enterprise Linux 9 STIG SCAP Benchmark

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Assessment Title

Rule Text

RHEL 9 must automatically lock an account when three unsuccessful logon attempts occur.

Description

Discussion Text

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. Satisfies: SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005

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

IA Controls

NIST SP 800-53

Not mappedCCI-000044Not mappedCCI-002238

References

DPMS Target Red Hat Enterprise Linux 9 DISA DPMS Target Red Hat Enterprise Linux 9 5551

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.rhel9os:def:258054
# RHEL 9 must automatically lock an account when three unsuccessful logon attempts occur.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# deny is set to 3 or less but not 0 in /etc/security/faillock.conf
# textfilecontent54_object (textfilecontent54_test)
test_1() {
  ( [ "$(sed -En 's/^\s*deny\s*=\s*([\d]+)\s*$/\1/p' '/etc/security/faillock.conf')" -le 3 ] ) && ( [ "$(sed -En 's/^\s*deny\s*=\s*([\d]+)\s*$/\1/p' '/etc/security/faillock.conf')" -gt 0 ] )
}

if test_1; 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
# OVAL Definition: oval:mil.disa.stig.rhel9os:def:258054

if [ ! -f "/etc/security/faillock.conf" ]; then
  echo "PASS"
  exit 0
fi

if grep -q "^\\s*deny\\s*=\\s*3\\s*$" /etc/security/faillock.conf; then
  echo "PASS"
  exit 0
fi

if grep -q "^\\s*deny\\s*=\\s*[0-9]+\\s*$" /etc/security/faillock.conf && ! grep -q "^\\s*deny\\s*=\\s*0\\s*$" /etc/security/faillock.conf; then
  echo "FAIL"
  exit 1
fi

echo "PASS"
exit 0

Remediation

Configure RHEL 9 to lock an account when three unsuccessful logon attempts occur.

Add/modify the "/etc/security/faillock.conf" file to match the following line:

deny = 3