pam_ldap: Authentication bypass vulnerability

Background

pam_ldap is a Pluggable Authentication Module which allows authentication against LDAP directories.

Description

When a pam_ldap client attempts to authenticate against an LDAP server that omits the optional error value from the PasswordPolicyResponseValue, the authentication attempt will always succeed.

Impact

A remote attacker may exploit this vulnerability to bypass the LDAP authentication mechanism, gaining access to the system possibly with elevated privileges.

Workaround

There is no known workaround at this time.

Resolution

All pam_ldap users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=sys-auth/pam_ldap-180"