Amazon Linux AMI Security Advisory: ALAS-2016-727
Advisory Release Date: 2017-01-04 14:36 Pacific
It was discovered that ntpq and ntpdc disclosed the origin timestamp to unauthenticated clients, which could permit such clients to forge the server's replies. (CVE-2015-8139 )
The process_packet function in ntp_proto.c in ntpd in NTP 4.x before 4.2.8p8 allows remote attackers to cause a denial of service (peer-variable modification) by sending spoofed packets from many source IP addresses in a certain scenario, as demonstrated by triggering an incorrect leap indication. (CVE-2016-4954 )
ntpd in NTP 4.x before 4.2.8p8, when autokey is enabled, allows remote attackers to cause a denial of service (peer-variable clearing and association outage) by sending (1) a spoofed crypto-NAK packet or (2) a packet with an incorrect MAC value at a certain time. (CVE-2016-4955 )
ntpd in NTP 4.x before 4.2.8p8 allows remote attackers to cause a denial of service (interleaved-mode transition and time change) via a spoofed broadcast packet. This vulnerability exists because of an incomplete fix for CVE-2016-1548 . (CVE-2016-4956 )
Run yum update ntp to update your system.