SV-204422r982201: The Red Hat Enterprise Linux operating system must be configured so that passwords are prohibited from reuse for a minimum of five generations. | Red Hat Enterprise Linux 7 STIG SCAP Benchmark

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Assessment Title

Rule Text

The Red Hat Enterprise Linux operating system must be configured so that passwords are prohibited from reuse for a minimum of five generations.

Description

Discussion Text

Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. If the information system or application allows the user to consecutively reuse their password when that password has exceeded its defined lifetime, the end result is a password that is not changed per policy requirements.

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

IA Controls

NIST SP 800-53

Not mappedCCI-000200V-71933SV-86557

References

DPMS Target Red Hat Enterprise Linux 7 DISA DPMS Target Red Hat Enterprise Linux 7 2899

Checks

OVAL

oval:mil.disa.stig.rhel7:var:3806 ← xccdf_mil.disa.stig_value_var_password_pam_unix_remember

DISA STIG (Manual Reference)

Verify the operating system prohibits password reuse for a minimum of five generations.

Check for the value of the "remember" argument in "/etc/pam.d/system-auth" and "/etc/pam.d/password-auth" with the following command:

     # grep -i remember /etc/pam.d/system-auth /etc/pam.d/password-auth
     password     requisite     pam_pwhistory.so use_authtok remember=5 retry=3

If the line containing the "pam_pwhistory.so" line does not have the "remember" module argument set, is commented out, or the value of the "remember" module argument is set to less than "5", this is a finding.

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.rhel7:def:486
# The Red Hat Enterprise Linux operating system must be configured so that passwords are prohibited from reuse for a minimum of five generations.
# Per-module read mechanism curated from static teardown of DISA's SCC tool
# (SCAP Compliance Checker) -- see the SCC Automation Reference above.

# remember parameter of pam_pwhistory.so is set correctly in /etc/pam.d/system-auth
# textfilecontent54_object (textfilecontent54_test)
test_1() {
  [ "$(sed -En 's/^\s*password\s+(?:(?:requisite)|(?:required))\s+pam_pwhistory\.so[^#\n\r]*remember=([0-9]*).*$/\1/p' '/etc/pam.d/system-auth')" -ge 5 ]
}
# remember parameter of pam_pwhistory.so is set correctly in /etc/pam.d/password-auth
# textfilecontent54_object (textfilecontent54_test)
test_2() {
  [ "$(sed -En 's/^\s*password\s+(?:(?:requisite)|(?:required))\s+pam_pwhistory\.so[^#\n\r]*remember=([0-9]*).*$/\1/p' '/etc/pam.d/password-auth')" -ge 5 ]
}

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
# OVAL Definition: oval:mil.disa.stig.rhel7:def:486
if [ ! -f "/etc/pam.d/system-auth" ]; then echo "PASS"; exit 0; fi; if [ ! -s "/etc/pam.d/system-auth" ]; then echo "PASS"; exit 0; fi; if grep -q "^\\s*password\\s+requisite\\s+pam_pwhistory\\.so[^#\\n\\r]*remember=[5-9][0-9]*" "/etc/pam.d/system-auth"; then echo "PASS"; exit 0; else echo "FAIL"; exit 1; fi
if [ ! -f "/etc/pam.d/password-auth" ]; then echo "PASS"; exit 0; fi; if [ ! -s "/etc/pam.d/password-auth" ]; then echo "PASS"; exit 0; fi; if grep -q "^\\s*password\\s+requisite\\s+pam_pwhistory\\.so[^#\\n\\r]*remember=[5-9][0-9]*" "/etc/pam.d/password-auth"; then echo "PASS"; exit 0; else echo "FAIL"; exit 1; fi

Remediation

Configure the operating system to prohibit password reuse for a minimum of five generations.

Add the following line in "/etc/pam.d/system-auth" (or modify the line to have the required value):

password     requisite     pam_pwhistory.so remember=5 retry=3

Add the following line in "/etc/pam.d/password-auth" (or modify the line to have the required value):

password     requisite     pam_pwhistory.so use_authtok remember=5 retry=3
   
Note: Per requirement RHEL-07-010199, RHEL 7 must be configured to not overwrite custom authentication configuration settings while using the authconfig utility; otherwise, manual changes to the listed files will be overwritten whenever the authconfig utility is used.