Zero-day vulnerability in ntp

Denial of service

This vulnerability was the cause of a record-sized NTP reflection attack in late 2013 and early 2014. We consider this a zero-day vulnerability as it was exploited in the wild before the official patch release.

Vulnerability details

Advisory: SB2013061201 - Denial of service in ntp

Vulnerable component: ntp

CVE-ID: CVE-2013-5211

CVSSv3 score: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:F/RL:O/RC:C

CWE-ID: CWE-20 - Improper Input Validation


The vulnerability allows a remote attacker to cause DoS conditions on the target system.

The weakness exists due to an error in the monlist feature in ntp_request.c. By sending a specially crafted REQ_MON_GETLIST or REQ_MON_GETLIST_1 request, a remote attacker can consume available CPU resources and cause the server to crash.

Successful exploitation of the vulnerability results in denial of service on the vulnerable system.

Note: the vulnerability was being actively exploited.

Public Exploits: