CVE-2016-4953 Denial of service in n/a

High 7.5 Published 5 Jul 2016 Updated 6 Aug 2024

Remote attackers can cause a denial of service in NTP by sending spoofed crypto-NAK packets with incorrect authentication data.

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

What is CVE-2016-4953?

CVE-2016-4953 is a high-severity denial of service vulnerability in Ntp Ntp, published on 5 Jul 2016. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

ntpd in NTP 4.x before 4.2.8p8 allows remote attackers to cause a denial of service (ephemeral-association demobilization) by sending a spoofed crypto-NAK packet with incorrect authentication data at a certain time.

Weakness: CWE-287

Which versions are affected by CVE-2016-4953?

It affects 12 products.

Products include Ntp Ntp, Opensuse Leap, Opensuse Opensuse, Oracle Solaris, Siemens Simatic Net Cp 443-1 Opc Ua Firmware, Siemens Tim 4r-Ie Dnp3 Firmware and 6 more.

How do I fix CVE-2016-4953?

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-2016-4953 being exploited?

There is no known exploitation of CVE-2016-4953 in the wild and no public exploit code.

All Ntp Ntp vulnerabilities

Sources

Also known as DEBIAN-CVE-2016-4953, GHSA-26jw-7mv6-89rj.