(RHSA-2017:0252) Moderate: ntp security update

The Network Time Protocol (NTP) is used to synchronize a computer’s time with another referenced time source. These packages include the ntpd service which continuously adjusts system time and utilities used to query and configure the ntpd service.

Security Fix(es):

• It was found that when ntp is configured with rate limiting for all associations the limits are also applied to responses received from its configured sources. A remote attacker who knows the sources can cause a denial of service by preventing ntpd from accepting valid responses from its sources. (CVE-2016-7426)

• A flaw was found in the control mode functionality of ntpd. A remote attacker could send a crafted control mode packet which could lead to information disclosure or result in DDoS amplification attacks. (CVE-2016-9310)

• A flaw was found in the way ntpd implemented the trap service. A remote attacker could send a specially crafted packet to cause a null pointer dereference that will crash ntpd, resulting in a denial of service. (CVE-2016-9311)

• A flaw was found in the way ntpd running on a host with multiple network interfaces handled certain server responses. A remote attacker could use this flaw which would cause ntpd to not synchronize with the source. (CVE-2016-7429)

• A flaw was found in the way ntpd calculated the root delay. A remote attacker could send a specially-crafted spoofed packet to cause denial of service or in some special cases even crash. (CVE-2016-7433)