NTP Monlist Feature Enabled

Summary
NTP is prone to a remote denial-of-service vulnerability because it fails to properly handle certain incoming network packets.
Impact
Successfully exploiting this issue may allow an attacker to cause a denial of service.
Solution
Update to NTP 4.2.7p26 or newer or set 'disable monitor' in ntp.conf.
Insight
The monlist feature in ntp_request.c in ntpd in NTP before 4.2.7p26 allows remote attackers to cause a denial of service (traffic amplification) via forged (1) REQ_MON_GETLIST or (2) REQ_MON_GETLIST_1 requests, as exploited in the wild in December 2013.
Affected
NTP before 4.2.7p26
Detection
Send a NTP monlist request and check the response.
References