SV-260549r958388: Ubuntu 22.04 LTS must automatically lock an account until the locked account is released by an administrator when three unsuccessful logon attempts have been made. | Canonical Ubuntu 22.04 LTS STIG SCAP Benchmark

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Assessment Title

Rule Text

Ubuntu 22.04 LTS must automatically lock an account until the locked account is released by an administrator when three unsuccessful logon attempts have been made.

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-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-000044Not mappedCCI-002238

References

DPMS Target Canonical Ubuntu 22.04 LTS DISA DPMS Target Canonical Ubuntu 22.04 LTS 5594

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.ubuntu2204os:def:260549
# Ubuntu 22.04 LTS must automatically lock an account until the locked account is released by an administrator when three unsuccessful logon attempts have been made.
# 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 module authfail is present in /etc/pam.d/common-auth file
# textfilecontent54_object (textfilecontent54_test)
test_1() {
  grep -Pq '^\s*auth\s+\[default=die\]\s+pam_faillock\.so\s+authfail\s*$' '/etc/pam.d/common-auth' &>/dev/null
}
# pam_faillock.so module authsucc is present in /etc/pam.d/common-auth file
# textfilecontent54_object (textfilecontent54_test)
test_2() {
  grep -Pq '^\s*auth\s+sufficient\s+pam_faillock\.so\s+authsucc\s*$' '/etc/pam.d/common-auth' &>/dev/null
}
# pam_faillock.so is used with audit
# textfilecontent54_object (textfilecontent54_test)
test_3() {
  grep -Pq '^\s*audit\s*$' '/etc/security/faillock.conf' &>/dev/null
}
# pam_faillock.so is used with silent
# textfilecontent54_object (textfilecontent54_test)
test_4() {
  grep -Pq '^\s*silent\s*$' '/etc/security/faillock.conf' &>/dev/null
}
# pam_faillock.so is used with deny set to 3 or less
# textfilecontent54_object (textfilecontent54_test)
test_5() {
  [ "$(sed -En 's/^\s*deny\s*=\s*([0-9])+\s*$/\1/p' '/etc/security/faillock.conf')" -le 3 ]
}
# pam_faillock.so is used with fail_interval set to 900 or less
# textfilecontent54_object (textfilecontent54_test)
test_6() {
  [ "$(sed -En 's/^\s*fail_interval\s*=\s*([0-9]+)+\s*$/\1/p' '/etc/security/faillock.conf')" -le 900 ]
}
# pam_faillock.so is used with unlock_time set to 0
# textfilecontent54_object (textfilecontent54_test)
test_7() {
  [ "$(sed -En 's/^\s*unlock_time\s*=\s*([0-9])+\s*$/\1/p' '/etc/security/faillock.conf')" -eq 0 ]
}

if ( test_1 && test_2 && test_3 && test_4 && test_5 && test_6 && test_7 ); then
  echo "PASS"
else
  echo "FAIL"
fi

Remediation

Configure Ubuntu 22.04 LTS to utilize the "pam_faillock" module.  
 
Add or modify the following lines in the "/etc/pam.d/common-auth" file, below the "auth" definition for "pam_unix.so":  
 
auth     [default=die]  pam_faillock.so authfail 
auth     sufficient          pam_faillock.so authsucc 
 
Configure the "pam_faillock" module to use the following options. 
 
Add or modify the following lines in the "/etc/security/faillock.conf" file: 
 
audit 
silent 
deny = 3 
fail_interval = 900 
unlock_time = 0