Steve Rigler discovered that the PAM module for authentication against LDAP servers processes PasswordPolicyReponse control messages incorrectly, which might lead to an attacker being able to login into a suspended system account.
For the stable distribution (sarge) this problem has been fixed in version 178-1sarge3. Due to technical problems with the security buildd infrastructure this update lacks a build for the Sun Sparc architecture. It will be released as soon as the problems are resolved.
For the unstable distribution (sid) this problem has been fixed in version 180-1.2.
We recommend that you upgrade your libpam-ldap package.