The symmetric-key feature in the receive function in ntp_proto.c in ntpd in NTP 3.x and 4.x before 4.2.8p2 performs state-variable updates upon receiving certain invalid packets, which makes it easier for man-in-the-middle attackers to cause a denial of service (synchronization loss) by spoofing the source IP address of a peer.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Ntp | Ntp | * | 4.2.7p444 (including) |