CVE-2016-2516 Denial of service in n/a

Medium 5.3 Published 30 Jan 2017 Updated 5 Aug 2024

Remote attackers can crash the NTP daemon by sending repeated unconfig directives from the same IP when mode7 is enabled.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2016-2516?

CVE-2016-2516 is a medium-severity denial of service vulnerability in Ntp Ntp, published on 30 Jan 2017. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

NTP before 4.2.8p7 and 4.3.x before 4.3.92, when mode7 is enabled, allows remote attackers to cause a denial of service (ntpd abort) by using the same IP address multiple times in an unconfig directive.

Weakness: CWE-20

Which versions are affected by CVE-2016-2516?

It affects 1 product.

Products include Ntp Ntp.

How do I fix CVE-2016-2516?

Upgrade to a fixed version.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2016-2516 being exploited?

There is no known exploitation of CVE-2016-2516 in the wild and no public exploit code.

All Ntp Ntp vulnerabilities

Sources

Also known as DEBIAN-CVE-2016-2516, GHSA-r7jh-6376-3vr2, UBUNTU-CVE-2016-2516.