Secunia Security Advisory – Ubuntu has issued an update for ntp. This fixes a vulnerability, which can be exploited by malicious people to cause a DoS (Denial of Service).
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/83652/sa37639.txt
Source: https://packetstormsecurity.com/files/83652/Secunia-Security-Advisory-37639.html