SV-258102r1045207: RHEL 9 must enforce password complexity by requiring that at least one lowercase character be used. | Red Hat Enterprise Linux 9 STIG SCAP Benchmark

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Assessment Title

Rule Text

RHEL 9 must enforce password complexity by requiring that at least one lowercase character be used.

Description

Discussion Text

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised. Requiring a minimum number of lowercase characters makes password guessing attacks more difficult by ensuring a larger search space.

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

IA Controls

NIST SP 800-53

Not mappedCCI-004066Not mappedCCI-000193

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:258102
# RHEL 9 must enforce password complexity by requiring that at least one lowercase character be used.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# at least one lowercase character is required
# textfilecontent54_object (textfilecontent54_test)
test_1() {
  ( [ "$(sed -En 's/^\s*lcredit\s*=\s*(-?\d*)\s*(?:#.*)?$/\1/p' '/etc/security/pwquality.conf')" -lt 0 ] ) || ( [ "$(grep -rhP --include='*.conf' '^\s*lcredit\s*=\s*(-?\d*)\s*(?:#.*)?$' '/etc/security/pwquality.conf.d' | sed -En 's/^\s*lcredit\s*=\s*(-?\d*)\s*(?:#.*)?$/\1/p')" -lt 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:258102
if [ ! -f "/etc/security/pwquality.conf" ] || [ ! $(grep -qE "^\\s*lcredit\\s*=\\s*(-?\\d+)\\s*(?:#.*)?$" /etc/security/pwquality.conf && echo "$MATCH" | grep -qE "^\\s*-?[1-9][0-9]*\\s*$") ]; then
    if [ ! -d "/etc/security/pwquality.conf.d" ] || [ ! -f "/etc/security/pwquality.conf.d/*.conf" ] || [ ! $(grep -rE "lcredit\\s*=\\s*(-?\\d+)\\s*" /etc/security/pwquality.conf.d/*.conf | grep -qE "^\\s*-?[1-9][0-9]*\\s*$") ]; then
        echo "FAIL"
        exit 1
    fi
fi
echo "PASS"
exit 0

Remediation

Configure RHEL 9 to enforce password complexity by requiring at least one lowercase character be used by setting the "lcredit" option.

Add or update the following line in the "/etc/security/pwquality.conf" file or a configuration file in the "/etc/security/pwquality.conf.d/" directory to contain the "lcredit" parameter:

lcredit = -1