Security considerations with using an NTP server

Question

What are the security considerations to keep in mind when using an NTP server to synchronize time? Wikipedia lists that there are no known high-risk vulnerabilities, but are there any lower risk weak points one should be aware of?

Also, are there any special concerns when using NTP pool servers?

Answer 1

Paper written for GIAC qualification with in depth analysis of NTP security.

An overview of NTP that's a little less verbose.

NTP is therefore vulnerable to security threats, whether from a malicious hacker who wants to alter the timestamp to commit fraud or a DDoS attack (Distributed Denial of Service - normally caused by malicious malware that floods a server with traffic) that blocks server access.

With regards to the pool servers, please remember they're volunteered servers.

From what I've read in the past, unless you have time critical tasks the highest risk is DDOS.