USN-1140-1: PAM vulnerabilities

30 May 2011

pam vulnerabilities

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

  • Ubuntu 11.04
  • Ubuntu 10.10
  • Ubuntu 10.04 LTS
  • Ubuntu 8.04 LTS

Summary

An attacker could cause PAM to read or delete arbitrary files or cause it to crash.

Software Description

  • pam - Pluggable Authentication Modules

Details

Marcus Granado discovered that PAM incorrectly handled configuration files with non-ASCII usernames. A remote attacker could use this flaw to cause a denial of service, or possibly obtain login access with a different users username. This issue only affected Ubuntu 8.04 LTS. (CVE-2009-0887)

It was discovered that the PAM pam_xauth, pam_env and pam_mail modules incorrectly handled dropping privileges when performing operations. A local attacker could use this flaw to read certain arbitrary files, and access other sensitive information. (CVE-2010-3316, CVE-2010-3430, CVE-2010-3431, CVE-2010-3435)

It was discovered that the PAM pam_namespace module incorrectly cleaned the environment during execution of the namespace.init script. A local attacker could use this flaw to possibly gain privileges. (CVE-2010-3853)

It was discovered that the PAM pam_xauth module incorrectly handled certain failures. A local attacker could use this flaw to delete certain unintended files. (CVE-2010-4706)

It was discovered that the PAM pam_xauth module incorrectly verified certain file properties. A local attacker could use this flaw to cause a denial of service. (CVE-2010-4707)

Update instructions

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

Ubuntu 11.04
libpam-modules - 1.1.2-2ubuntu8.2
Ubuntu 10.10
libpam-modules - 1.1.1-4ubuntu2.2
Ubuntu 10.04 LTS
libpam-modules - 1.1.1-2ubuntu5.2
Ubuntu 8.04 LTS
libpam-modules - 0.99.7.1-5ubuntu6.3

To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.

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

References