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. Updated packages are available from security.ubuntu.com.
========================================================================== 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 1.0.5-6ubuntu22.214.171.124 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: http://www.ubuntu.com/usn/usn-1308-1 CVE-2011-4089 Package Information: https://launchpad.net/ubuntu/+source/bzip2/1.0.5-6ubuntu126.96.36.199 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