NTP BUG 3119: Mode 6 unauthenticated trap information disclosure and DDoS vector
Last update: April 22, 2024 18:49 UTC (7e7bd5857)
Summary
Description
ntpd
does not enable trap service by default. If trap service has been explicitly enabled, an attacker can send a specially crafted packet to cause a null pointer dereference that will crash ntpd
, resulting in a denial of service.
Mitigation
- Implement BCP-38.
- Use
restrict default noquery ...
in your ntp.conf
file. Only allow mode 6 queries from trusted networks and hosts.
- Upgrade to 4.2.8p9 or later.
- Properly monitor your
ntpd
instances, and auto-restart ntpd
(without -g
) if it stops running.
Credit
This weakness was discovered by Matthew Van Gundy of Cisco.
Timeline