Multiple stack-based buffer overflows in ntpd in NTP before 4.2.8 allow remote attackers to execute arbitrary code via a crafted packet, related to (1) the crypto_recv function when the Autokey Authentication feature is used, (2) the ctl_putdata function, and (3) the configure function.
util/ntp-keygen.c in ntp-keygen in NTP before 4.2.7p230 uses a weak RNG seed, which makes it easier for remote attackers to defeat cryptographic protection mechanisms via a brute-force attack.
The config_auth function in ntpd in NTP before 4.2.7p11, when an auth key is not configured, improperly generates a key, which makes it easier for remote attackers to defeat cryptographic protection mechanisms via a brute-force attack.
The monlist feature in ntp_request.c in ntpd in NTP before 4.2.7p26 allows remote attackers to cause a denial of service (traffic amplification) via forged (1) REQ_MON_GETLIST or (2) REQ_MON_GETLIST_1 requests, as exploited in the wild in December 2013.