NTP users are strongly urged to take immediate action to ensure that their NTP daemons are not susceptible to being used in distributed denial-of-service (DDoS) attacks. Please also take this opportunity to defeat denial-of-service attacks by implementing Ingress and Egress filtering through BCP38.
ntp-4.2.8p15was released on 23 June 2020. It addresses 1 medium-severity security issue in ntpd, and provides 13 non-security bugfixes over 4.2.8p13.
Please see the NTP Security Notice for vulnerability and mitigation details.Are you using Autokey in production? If so, please contact Harlan - he's got some questions for you.
ntpdreceives a server response on a socket that corresponds to a different interface than was used for the request, the peer structure is updated to use the interface for new requests. If
ntpdis running on a host with multiple interfaces in separate networks and the operating system doesn't check source address in received packets (e.g.
rp_filteron Linux is set to 0), an attacker that knows the address of the source can send a packet with spoofed source address which will cause
ntpdto select wrong interface for the source and prevent it from sending new requests until the list of interfaces is refreshed, which happens on routing changes or every 5 minutes by default. If the attack is repeated often enough (once per second),
ntpdwill not be able to synchronize with the source.
ntpdinstances, and auto-restart
-g) if it stops running.