Network Time Protocol Daemon (ntpd) monlist Command Enabled DoS

high Nessus Plugin ID 71783
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The remote NTP server is affected by a denial of service vulnerability.


The version of ntpd running on the remote host has the 'monlist' command enabled. This command returns a list of recent hosts that have connected to the service. However, it is affected by a denial of service vulnerability in ntp_request.c that allows an unauthenticated, remote attacker to saturate network traffic to a specific IP address by using forged REQ_MON_GETLIST or REQ_MON_GETLIST_1 requests.
Furthermore, an attacker can exploit this issue to conduct reconnaissance or distributed denial of service (DDoS) attacks.


If using NTP from the Network Time Protocol Project, upgrade to NTP version 4.2.7-p26 or later. Alternatively, add 'disable monitor' to the ntp.conf configuration file and restart the service. Otherwise, limit access to the affected service to trusted hosts, or contact the vendor for a fix.

See Also

Plugin Details

Severity: High

ID: 71783

File Name: ntp_monlist_enabled.nasl

Version: 1.18

Type: remote

Family: Misc.

Published: 1/2/2014

Updated: 7/16/2018

Dependencies: ntp_open.nasl

Risk Information


Risk Factor: Medium

Score: 4.4


Risk Factor: Medium

Base Score: 5

Temporal Score: 3.9

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P

Temporal Vector: CVSS2#E:POC/RL:OF/RC:C


Risk Factor: High

Base Score: 7.5

Temporal Score: 6.7

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C

Vulnerability Information

CPE: cpe:2.3:a:ntp:ntp:*:*:*:*:*:*:*:*

Required KB Items: NTP/Running

Exploit Available: true

Exploit Ease: Exploits are available

Exploited by Nessus: true

Patch Publication Date: 4/24/2010

Vulnerability Publication Date: 4/20/2010

Reference Information

CVE: CVE-2013-5211

BID: 64692

CERT: 348126

EDB-ID: 33073

ICSA: 14-051-04