Secunia Security Advisory – Ubuntu has issued an update for grub2. This fixes a vulnerability which can be exploited by malicious people with physical access to conduct brute force attacks.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/83644/sa37632.txt
Source: https://packetstormsecurity.com/files/83644/Secunia-Security-Advisory-37632.html