Ubuntu Security Notice USN-175-1 – Thomas Biege discovered a flaw in the privilege dropping of the NTP server. When ntpd was configured to drop root privileges, and the group to run under was specified as a name (as opposed to a numeric group ID), ntpd changed to the wrong group. Depending on the actual group it changed to, this could either cause non-minimal privileges, or a malfunctioning ntp server if the group does not have the privileges that ntpd actually needs.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/39814/USN-175-1.txt
Source: https://packetstormsecurity.com/files/39814/Ubuntu-Security-Notice-175-1.html