USN-636-1: Postfix vulnerability

Ubuntu Security Notice USN-636-1

19th August, 2008

postfix vulnerability

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

  • Ubuntu 8.04 LTS
  • Ubuntu 7.10
  • Ubuntu 7.04
  • Ubuntu 6.06 LTS

Software description

  • postfix


Sebastian Krahmer discovered that Postfix was not correctly handling
mailbox ownership when dealing with Linux's implementation of hardlinking
to symlinks. In certain mail spool configurations, a local attacker
could exploit this to append data to arbitrary files as the root user.
The default Ubuntu configuration was not vulnerable.

Update instructions

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

Ubuntu 8.04 LTS:
postfix 2.5.1-2ubuntu1.1
Ubuntu 7.10:
postfix 2.4.5-3ubuntu1.2
Ubuntu 7.04:
postfix 2.3.8-2ubuntu0.2
Ubuntu 6.06 LTS:
postfix 2.2.10-1ubuntu0.2

To update your system, please follow these instructions:

In general, a standard system upgrade is sufficient to effect the
necessary changes.