Software Properties could be tricked into installing arbitrary PPA GPG keys.
David Black discovered that Software Properties incorrectly validated server certificates when performing secure connections to download PPA GPG key fingerprints. 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.
31 January 2012
A security issue affects these releases of Ubuntu and its derivatives:
Software Properties could be tricked into installing arbitrary PPA GPG keys.
David Black discovered that Software Properties incorrectly validated server certificates when performing secure connections to download PPA GPG key fingerprints. 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.
In general, a standard system update will make all the necessary changes.
Vulmon