The Network Time Protocol (NTP) is used to synchronize a computer's timewith a referenced time source.Robin Park and Dmitri Vinokurov discovered a flaw in the way ntpd handledcertain malformed NTP packets. ntpd logged information about all suchpackets and replied with an NTP packet that was treated as malformed whenreceived by another ntpd. A remote attacker could use this flaw to createan NTP packet reply loop between two ntpd servers via a malformed packetwith a spoofed source IP address and port, causing ntpd on those servers touse excessive amounts of CPU time and fill disk space with log messages.(CVE-2009-3563)All ntp users are advised to upgrade to this updated package, whichcontains a backported patch to resolve this issue. After installing theupdate, the ntpd daemon will restart automatically.