USN-959-1: PAM vulnerability

7 July 2010

pam vulnerability

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

  • Ubuntu 10.04 LTS
  • Ubuntu 9.10


Root privilege escalation via symlink following.

Software Description

  • pam - Pluggable Authentication Modules library


Denis Excoffier discovered that the PAM MOTD module in Ubuntu did not correctly handle path permissions when creating user file stamps. A local attacker could exploit this to gain root privilieges.

Update instructions

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

Ubuntu 10.04 LTS
libpam-modules - 1.1.1-2ubuntu5
Ubuntu 9.10
libpam-modules - 1.1.0-2ubuntu1.1

To update your system, please follow these instructions:

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