Aptdaemon could be tricked into installing arbitrary PPA GPG keys.
It was discovered that Aptdaemon incorrectly validated PPA GPG keys when importing from a keyserver. If a remote attacker were able to perform a man-in-the-middle attack, this flaw could be exploited to install altered package repository GPG keys.
17 December 2012
A security issue affects these releases of Ubuntu and its derivatives:
Aptdaemon could be tricked into installing arbitrary PPA GPG keys.
It was discovered that Aptdaemon incorrectly validated PPA GPG keys when importing from a keyserver. If a remote attacker were able to perform a man-in-the-middle attack, this flaw could be exploited to install altered package repository GPG keys.
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
After a standard system update you need to reboot your computer to make all the necessary changes.
Vulmon