Red Hat Security Advisory 2015-2520-01 – The Network Time Protocol is used to synchronize a computer’s time with a referenced time source. It was discovered that ntpd as a client did not correctly check timestamps in Kiss-of-Death packets. A remote attacker could use this flaw to send a crafted Kiss-of-Death packet to an ntpd client that would increase the client’s polling interval value, and effectively disable synchronization with the server.