Rule ID
SV-261364r996863_rule
Version
V1R4
By limiting the number of failed access 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. The pam_tally2.so module maintains a count of attempted accesses. This includes username entry into a logon field as well as password entry. With counting access attempts, it is possible to lock an account without presenting a password into the password field. This should be taken into consideration as it poses as an avenue for denial of service (DoS).
Verify SLEM 5 locks a user account after three consecutive failed access attempts until the locked account is released by an administrator with the following command:
> grep pam_tally2.so /etc/pam.d/common-auth
auth required pam_tally2.so onerr=fail deny=3
If "deny" set to a value other than "1", "2", or "3", if "onerr=fail" is missing, if the line is commented out, or the line is missing, this is a finding.Configure SLEM 5 to lock an account when three unsuccessful access attempts occur. Note: Manual changes to the listed files may be overwritten by the "pam-config" program. The "pam-config" program should not be used to update the configurations listed in this requirement. Add or modify the first line of the auth section in the "/etc/pam.d/common-auth" file to match the following line: auth required pam_tally2.so onerr=fail silent audit deny=3 Add or modify the following line in the "/etc/pam.d/common-account" file: account required pam_tally2.so