RHEL 9 must automatically lock an account when three unsuccessful logon attempts occur.

STIG ID: RHEL-09-411075  |  SRG: SRG-OS-000329-GPOS-00128 |  Severity: medium |  CCI: CCI-000044,CCI-002238 |  Vulnerability Id: V-258054

Vulnerability Discussion

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.

Satisfies: SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005

Check

Verify RHEL 9 is configured to lock an account after three unsuccessful logon attempts with the command:

$ grep 'deny =' /etc/security/faillock.conf

deny = 3

If the "deny" option is not set to "3" or less (but not "0"), is missing or commented out, this is a finding.

Fix

Configure RHEL 9 to lock an account when three unsuccessful logon attempts occur.

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

deny = 3
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