NTP BUG 3010: remote configuration trustedkey/requestkey/controlkey values are not properly validated

Last update: September 3, 2026 14:42 UTC (1eec487e7)

Summary

Resolved 4.2.8p7 26 Apr 2016
References Bug 3010 CVE-2016-2517
Affects All ntp-4 releases up to, but not including 4.2.8p7,
and 4.3.0 up to, but not including 4.3.92.		 Resolved in 4.2.8p7.
CVSS2 Score MED 4.9 AV:N/AC:H/Au:S/C:N/I:N/A:C
CVSS3 Score MED 4.2 CVSS:3.0/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:N/A:H

Description

If ntpd was expressly configured to allow for remote configuration, a malicious user who knows the controlkey for ntpq or the requestkey for ntpdc (if mode7 is expressly enabled) can create a session with ntpd and then send a crafted packet to ntpd that will change the value of the trustedkey, controlkey, or requestkey to a value that will prevent any subsequent authentication with ntpd until ntpd is restarted.

Mitigation

Credit

This weakness was discovered by Yihan Lian of the Cloud Security Team, Qihoo 360.

Timeline