NTP BUG 2946: Origin Leak: ntpq and ntpdc Disclose Origin Timestamp to Unauthenticated Clients

Last update: June 28, 2022 20:06 UTC (57417e17c)


Resolved 4.2.8p7 26 Apr 2016
References Bug 2946 CVE-2015-8139
Affects All ntp-4 releases up to, but not including 4.2.8p7. Resolved in 4.2.8p7.
CVSS2 Score MED 5.0 AV:N/AC:L/Au:N/C:P/I:P/A:N
CVSS3 Score MED 5.3 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N


To prevent off-path attackers from impersonating legitimate peers, clients require that the origin timestamp in a received response packet match the transmit timestamp from its last request to a given peer. Under assumption that only the recipient of the request packet will know the value of the transmit timestamp, this prevents an attacker from forging replies.



This weakness was discovered by Matthew Van Gundy of Cisco ASIG.