CVE-2016-4956 Denial of service in n/a

Medium 5.3 Published 5 Jul 2016 Updated 6 Aug 2024

Remote attackers can cause a denial of service in the NTP daemon via spoofed broadcast packets, affecting systems running NTP 4.x.

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

What is CVE-2016-4956?

CVE-2016-4956 is a medium-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 (interleaved-mode transition and time change) via a spoofed broadcast packet. NOTE: this vulnerability exists because of an incomplete fix for CVE-2016-1548.

Which versions are affected by CVE-2016-4956?

It affects 10 products.

Products include Novell Suse Manager, Ntp Ntp, Opensuse Leap, Opensuse Opensuse, Oracle Solaris, Siemens Simatic Net Cp 443-1 Opc Ua Firmware and 4 more.

How do I fix CVE-2016-4956?

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-2016-4956 being exploited?

There is no known exploitation of CVE-2016-4956 in the wild and no public exploit code.

All Ntp Ntp vulnerabilities

Sources

Also known as DEBIAN-CVE-2016-4956, GHSA-3cjf-rf3w-p8j9, UBUNTU-CVE-2016-4956.