FreeBSD Security Advisory – The ntpd(8) daemon is an implementation of the Network Time Protocol (NTP) used to synchronize the time of a computer system to a reference time source. When no authentication key is set in the configuration file, ntpd(8) would generate a random key that uses a non-linear additive feedback random number generator seeded with very few bits of entropy. The ntp-keygen(8) utility is also affected by a similar issue. When Autokey Authentication is enabled, for example if ntp.conf(5) contains a ‘crypto pw’ directive, a remote attacker can send a carefully crafted packet that can overflow a stack buffer. In ntp_proto.c, the receive() function is missing a return statement in the case when an error is detected.