SV-230336r1184268: RHEL 8 must automatically lock an account until the locked account is released by an administrator when three unsuccessful logon attempts occur during a 15-minute time period. | Red Hat Enterprise Linux 8 STIG SCAP Benchmark

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Assessment Title

Rule Text

RHEL 8 must automatically lock an account until the locked account is released by an administrator 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-force attacks, is reduced. Limits are imposed by locking the account. RHEL 8 can utilize the "pam_faillock.so" for this purpose. Note that manual changes to the listed files may be overwritten by the "authselect" program. From "Pam_Faillock" man pages: Note that the default directory that "pam_faillock" uses is usually cleared on system boot so the access will be reenabled after system reboot. If that is undesirable a different tally directory must be set with the "dir" option. Satisfies: SRG-OS-000021-GPOS-00005, SRG-OS-000329-GPOS-00128

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

IA Controls

NIST SP 800-53

Not mappedCCI-000044

References

DPMS Target Red Hat Enterprise Linux 8 DISA DPMS Target Red Hat Enterprise Linux 8 2921

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.rhel8os:def:230336
# RHEL 8 must automatically lock an account until the locked account is released by an administrator 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.

# pam_faillock.so preauth unlock_time value set to 0 in system-auth
# textfilecontent54_object (textfilecontent54_test)
test_1() {
  [ "$(sed -En 's/^\s*auth\s+required\s+pam_faillock\.so\s+preauth.*[ \t]+unlock_time=([0-9]+)(?:[ \t]+.*)?$/\1/p' '/etc/pam.d/system-auth')" -eq 0 ]
}
# pam_faillock.so preauth unlock_time value set to 0 in password-auth
# textfilecontent54_object (textfilecontent54_test)
test_2() {
  [ "$(sed -En 's/^\s*auth\s+required\s+pam_faillock\.so\s+preauth.*[ \t]+unlock_time=([0-9]+)(?:[ \t]+.*)?$/\1/p' '/etc/pam.d/password-auth')" -eq 0 ]
}
# pam_faillock.so authfail unlock_time value set to 0 in system-auth
# textfilecontent54_object (textfilecontent54_test)
test_3() {
  [ "$(sed -En 's/^\s*auth\s+required\s+pam_faillock\.so\s+authfail.*[ \t]+unlock_time=([0-9]+)(?:[ \t]+.*)?$/\1/p' '/etc/pam.d/system-auth')" -eq 0 ]
}
# pam_faillock.so authfail unlock_time value set to 0 in password-auth
# textfilecontent54_object (textfilecontent54_test)
test_4() {
  [ "$(sed -En 's/^\s*auth\s+required\s+pam_faillock\.so\s+authfail.*[ \t]+unlock_time=([0-9]+)(?:[ \t]+.*)?$/\1/p' '/etc/pam.d/password-auth')" -eq 0 ]
}

if ( test_1 && test_2 && test_3 && test_4 ); 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:mil.disa.stig.rhel8os:def:230336
if [ ! -f "/etc/pam.d/system-auth" ] || [ ! -f "/etc/pam.d/password-auth" ]; then echo "FAIL"; exit 1; fi
if ! grep -q "^\\s*auth\\s+required\\s+pam_faillock\\.so\\s+preauth.*[ \\t]+unlock_time=0.*" /etc/pam.d/system-auth && ! grep -q "^\\s*auth\\s+required\\s+pam_faillock\\.so\\s+authfail.*[ \\t]+unlock_time=0.*" /etc/pam.d/system-auth && ! grep -q "^\\s*account\\s+required\\s+pam_faillock\\.so.*" /etc/pam.d/system-auth && ! grep -q "^\\s*auth\\s+required\\s+pam_faillock\\.so\\s+preauth.*[ \\t]+unlock_time=0.*" /etc/pam.d/password-auth && ! grep -q "^\\s*auth\\s+required\\s+pam_faillock\\.so\\s+authfail.*[ \\t]+unlock_time=0.*" /etc/pam.d/password-auth && ! grep -q "^\\s*account\\s+required\\s+pam_faillock\\.so.*" /etc/pam.d/password-auth ]; then echo "FAIL"; exit 1; fi
echo "PASS"; exit 0

Remediation

Configure the operating system to lock an account until released by an administrator when three unsuccessful logon attempts occur in 15 minutes.

Add/Modify the appropriate sections of the "/etc/pam.d/system-auth" and "/etc/pam.d/password-auth" files to match the following lines:

auth required pam_faillock.so preauth dir=/var/log/faillock silent audit deny=3 even_deny_root fail_interval=900 unlock_time=0
auth required pam_faillock.so authfail dir=/var/log/faillock unlock_time=0
account required pam_faillock.so

The "sssd" service must be restarted for the changes to take effect. To restart the "sssd" service, run the following command:

$ sudo systemctl restart sssd.service