Description

When configuring saltstack to authentificate via the salt.auth.pam module. The authorization of a account validity is missing. Therefore expired accounts, or accounts with expired passwords, can still login.

Proof of Concept

Configure salt with salt.auth.pam and run it with an expired account. To expire an PAM account use: chage -E0 <username>

Impact

After successfull authentication with pam_authenticateit’s necessary to check the validity of an account with pam_acct_mgmt(). This is done, but the return value is discarded and only the return value of pam_authenticateis being used which results in skipping for authorization completely. Depending on how salt is configured this can become pretty severe. You don’t revoke privileges for an account without a reason. As always I assume that the salt developers could estimate the severity way better than I could, so feel free to correct it.