Synopsis
The remote network time service has a denial of service vulnerability.
Description
The version of ntpd running on the remote host has a denial of service vulnerability. It responds to mode 7 error packets with its own mode 7 error packets. A remote attacker could exploit this by sending a mode 7 error response with a spoofed IP header, setting the source and destination IP addresses to the IP address of the target. This would cause ntpd to respond to itself endlessly, consuming excessive amounts of CPU, resulting in a denial of service.
Solution
Upgrade to NTP 4.2.4p8 / 4.2.6 or later.