NTP BUG 2921: Password Length Memory Corruption Vulnerability
Last update: June 28, 2022 20:06 UTC (57417e17c)
||21 Oct 2015
||All ntp-4 releases up to, but not including 4.2.8p4,
and 4.3.0 up to, but not including 4.3.77.
|Resolved in 4.2.8p4.
||0.0 best case, 1.7 usual case, 6.8, worst case
ntpd is configured to allow remote configuration, and if the (possibly spoofed) source IP address is allowed to send remote configuration requests, and if the attacker knows the remote configuration password or if
ntpd was (foolishly) configured to disable authentication, then an attacker can send a set of packets to
ntpd that may cause it to crash, with the hypothetical possibility of a small code injection.
- Implement BCP-38.
- Upgrade to 4.2.8p4 or later.
- If you are unable to upgrade, remote configuration of NTF’s
- an explicitly configured “trusted” key. Only configure this if you need it.
- access from a permitted IP address. You choose the IPs.
- authentication. Don’t disable it. Practice secure key safety.
- Monitor your
This weakness was discovered by Yves Younan and Aleksander Nikolich of Cisco Talos.