=========================================================================Ubuntu Security Notice USN-1308-1
December 14, 2011

bzip2 vulnerability
=========================================================================
A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 11.10
- Ubuntu 11.04
- Ubuntu 10.10
- Ubuntu 10.04 LTS
- Ubuntu 8.04 LTS

Summary:

Executables compressed by bzexe could be made to run programs as your
login.

Software Description:
- bzip2: high-quality block-sorting file compressor - utilities

Details:

vladz discovered that executables compressed by bzexe insecurely create
temporary files when they are ran. A local attacker could exploit this issue to
execute arbitrary code as the user running a compressed executable.

Update instructions:

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

Ubuntu 11.10:
  bzip2                           1.0.5-6ubuntu1.11.10.1

Ubuntu 11.04:
  bzip2                           1.0.5-6ubuntu1.11.04.1

Ubuntu 10.10:
  bzip2                           1.0.5-4ubuntu1.1

Ubuntu 10.04 LTS:
  bzip2                           1.0.5-4ubuntu0.2

Ubuntu 8.04 LTS:
  bzip2                           1.0.4-2ubuntu4.2

In general, a standard system update will make all the necessary changes to
the bzexe utility. If you have previously used bzexe to compress any
executables, they need to be recompressed using the updated version.

References:
  https://ubuntu.com/security/notices/USN-1308-1
  CVE-2011-4089

Package Information:
  https://launchpad.net/ubuntu/+source/bzip2/1.0.5-6ubuntu1.11.10.1
  https://launchpad.net/ubuntu/+source/bzip2/1.0.5-6ubuntu1.11.04.1
  https://launchpad.net/ubuntu/+source/bzip2/1.0.5-4ubuntu1.1
  https://launchpad.net/ubuntu/+source/bzip2/1.0.5-4ubuntu0.2
  https://launchpad.net/ubuntu/+source/bzip2/1.0.4-2ubuntu4.2