SV-258056r1045143: RHEL 9 must automatically lock an account when three unsuccessful logon attempts occur during a 15-minute time period. | 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 during a 15-minute time period.

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-forcing, 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:258056
# RHEL 9 must automatically lock an account when three unsuccessful logon attempts occur during a 15-minute time period.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# /etc/security/faillock.conf:fail_interval <=900 and !=0
# textfilecontent54_object (textfilecontent54_test)
test_1() {
  ( [ "$(sed -En 's/^\s*fail_interval\s*=\s*([\d]+)\s*$/\1/p' '/etc/security/faillock.conf')" -le 900 ] ) && ( [ "$(sed -En 's/^\s*fail_interval\s*=\s*([\d]+)\s*$/\1/p' '/etc/security/faillock.conf')" -ne 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:258056
if [ ! -f "/etc/security/faillock.conf" ]; then echo "PASS"; exit 0; fi
if grep -qE "^\\s*fail_interval\\s*=\\s*(900)\\s*$" /etc/security/faillock.conf && ! grep -qE "^\\s*fail_interval\\s*=\\s*0\\s*$" /etc/security/faillock.conf; then echo "PASS"; exit 0; else echo "FAIL"; exit 1; fi

Remediation

To configure RHEL 9 to lock out the "root" account after a number of incorrect logon attempts within 15 minutes using "pam_faillock.so", enable the feature using the following command:
 
$ sudo authselect enable-feature with-faillock  

Then edit the "/etc/security/faillock.conf" file as follows:

fail_interval = 900