5.8 - USN-2935-3

A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 12.04 LTS

Summary:

USN-2935-1 introduced a regression in PAM.

Software Description: - pam: Pluggable Authentication Modules

Details:

USN-2935-1 fixed vulnerabilities in PAM. The updates contained a packaging change that prevented upgrades in certain multiarch environments. USN-2935-2 intended to fix the problem but was incomplete for Ubuntu 12.04 LTS. This update fixes the problem in Ubuntu 12.04 LTS.

We apologize for the inconvenience.

Original advisory details:

It was discovered that the PAM pam_userdb module incorrectly used a
case-insensitive method when comparing hashed passwords. A local attacker
could possibly use this issue to make brute force attacks easier. This
issue only affected Ubuntu 12.04 LTS and Ubuntu 14.04 LTS. (CVE-2013-7041)

Sebastian Krahmer discovered that the PAM pam_timestamp module incorrectly
performed filtering. A local attacker could use this issue to create
arbitrary files, or possibly bypass authentication. This issue only
affected Ubuntu 12.04 LTS and Ubuntu 14.04 LTS. (CVE-2014-2583)

Sebastien Macke discovered that the PAM pam_unix module incorrectly handled
large passwords. A local attacker could possibly use this issue in certain
environments to enumerate usernames or cause a denial of service.
(CVE-2015-3238)

Update instructions:

The problem can be corrected by updating your system to the following package versions:

Ubuntu 12.04 LTS:
libpam-modules 1.1.3-7ubuntu2.3

In general, a standard system update will make all the necessary changes.

References:
http://www.ubuntu.com/usn/usn-2935-3
http://www.ubuntu.com/usn/usn-2935-1
http://www.ubuntu.com/usn/usn-2935-2, https://launchpad.net/bugs/1558597

Package Information:
https://launchpad.net/ubuntu/+source/pam/1.1.3-7ubuntu2.3