Implementation of pam_tally2.so counts successful logins as failures

This document (7011883) is provided subject to the disclaimer at the end of this document.

Environment

SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Server 12
SUSE Linux Enterprise Server 11

Situation

After adding pam_tally2.so to /etc/pam.d/common-auth file like this:

auth    required    pam_env.so
auth    required    pam_unix2.so
auth    required    pam_tally2.so onerr=fail deny=6

After each successful login, the failed login count is incremented. After the number of successful logins matches the maximum failed login count the account is locked and the account has to be manually reset.

The user logs in successfully.

user1@server:~> ssh geeko@sles15sp3
Password:
Last login: Fri Jul 16 10:56:54 2021 from 192.168.0.170
geeko@sles15sp3:~>

However, on the server pam_tally2 shows a login failure.

sles15sp3:~ # pam_tally2
Login Failures Latest failure From
geeko 1 07/16/21 10:57:16 192.168.0.170

When the user correctly logs in after the sixth attempt (matching deny=6 above), they get an error and locked account.

user1@server:~> ssh geeko@sles15sp3
Password:
Account locked due to 7 failed logins

The pam_tally2 command shows too many failed login attempts.

sles15sp3:~ # pam_tally2
Login Failures Latest failure From
geeko 7 07/16/21 10:59:50 192.168.0.170

Resolution

By adding the following line to the /etc/pam.d/common-account file this problem will be resolved:

account required pam_tally2.so

Disclaimer

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