STIGQter: STIG Summary: Tri-Lab Operating System Stack (TOSS) 4 Security Technical Implementation Guide Version: 2 Release: 6 Benchmark Date: 01 Jul 2026:

TOSS must automatically lock an account until the locked account is released by an administrator when three unsuccessful logon attempts in 15 minutes occur.

DISA Rule

SV-252957r958736_rule

Vulnerability Number

V-252957

Group Title

SRG-OS-000329-GPOS-00128

Rule Version

TOSS-04-020170

Severity

CAT II

CCI(s)

CCI-002238 - Automatically lock the account or node for either an organization-defined time period, until the locked account or node is released by an administrator, or delays the next logon prompt according to the organization-defined delay algorithm when the maximum number of unsuccessful logon attempts is exceeded.

Weight

Fix Recommendation

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

Add and/or 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
auth required pam_faillock.so authfail
account required pam_faillock.so

Add and/or modify the "/etc/security/faillock.conf" file to match the following line:

unlock_time = 0

Check Contents

Check that the system locks an account after three unsuccessful logon attempts within a period of 15 minutes until released by an administrator with the following commands.

Note: If a centralized authentication platform (AD, IdM, LDAP, etc) is utilized for authentication, then this requirement is not applicable, to allow the centralized platform to solely manage user lockout.

Verify the pam_faillock.so module is present in the "/etc/pam.d/system-auth" and " /etc/pam.d/password-auth" files:

$ sudo grep pam_faillock.so /etc/pam.d/system-auth /etc/pam.d/password-auth

/etc/pam.d/system-auth:auth required pam_faillock.so preauth
/etc/pam.d/system-auth:auth required pam_faillock.so authfail
/etc/pam.d/system-auth:account required pam_faillock.so
/etc/pam.d/password-auth:auth required pam_faillock.so preauth
/etc/pam.d/password-auth:auth required pam_faillock.so authfail
/etc/pam.d/password-auth:account required pam_faillock.so preauth

If the pam_failllock.so module is not present in the "/etc/pam.d/system-auth" and " /etc/pam.d/password-auth" files, this is a finding.

Verify the "/etc/security/faillock.conf" file is configured to lock an account until released by an administrator after three unsuccessful logon attempts:

$ sudo grep 'unlock_time =' /etc/security/faillock.conf
unlock_time = 0

If the "unlock_time" option is not set to "0", is missing or commented out, this is a finding.

Vulnerability Number

V-252957

Documentable

False

Rule Version

TOSS-04-020170

Severity Override Guidance

Check Content Reference

Target Key

5469