It was discovered that the Exim daemon did not correctly handle certain DKIM identities. A remote attacker could send specially crafted email to run arbitrary code as the Exim user. Updated packages are available from security.ubuntu.com.
========================================================================== Ubuntu Security Notice USN-1135-1 May 25, 2011 exim4 vulnerability ========================================================================== A security issue affects these releases of Ubuntu and its derivatives: - Ubuntu 11.04 - Ubuntu 10.10 - Ubuntu 10.04 LTS Summary: An attacker could send crafted input to Exim and cause it to run programs as the Exim user. Software Description: - exim4: metapackage to ease Exim MTA (v4) installation Details: It was discovered that the Exim daemon did not correctly handle certain DKIM identities. A remote attacker could send specially crafted email to run arbitrary code as the Exim user. Update instructions: The problem can be corrected by updating your system to the following package versions: Ubuntu 11.04: exim4-daemon-custom 4.74-1ubuntu1.2 exim4-daemon-heavy 4.74-1ubuntu1.2 exim4-daemon-light 4.74-1ubuntu1.2 Ubuntu 10.10: exim4-daemon-custom 4.72-1ubuntu1.3 exim4-daemon-heavy 4.72-1ubuntu1.3 exim4-daemon-light 4.72-1ubuntu1.3 Ubuntu 10.04 LTS: exim4-daemon-custom 4.71-3ubuntu1.3 exim4-daemon-heavy 4.71-3ubuntu1.3 exim4-daemon-light 4.71-3ubuntu1.3 In general, a standard system update will make all the necessary changes. References: CVE-2011-1407 Package Information: https://launchpad.net/ubuntu/+source/exim4/4.74-1ubuntu1.2 https://launchpad.net/ubuntu/+source/exim4/4.72-1ubuntu1.3 https://launchpad.net/ubuntu/+source/exim4/4.71-3ubuntu1.3