SLEM 5 must lock an account after three consecutive invalid access attempts.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-261364	SLEM-05-412020	SV-261364r996863_rule		Medium

Description
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).

Description

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).

STIG	Date
SUSE Linux Enterprise Micro (SLEM) 5 Security Technical Implementation Guide	2024-06-04

Details

Check Text ( C-65093r996537_chk )
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.

Check Text ( C-65093r996537_chk )

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.

Fix Text (F-65001r996538_fix)
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

Fix Text (F-65001r996538_fix)

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