FreeBSD VuXML: Documenting security issues in FreeBSD and the FreeBSD Ports Collection

ntpd DRDoS / Amplification Attack using ntpdc monlist command

Affected packages
ntp < 4.2.7p26

Details

VuXML ID 3d95c9a7-7d5c-11e3-a8c1-206a8a720317
Discovery 2014-01-01
Entry 2014-01-14

ntp.org reports:

Unrestricted access to 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

Use noquery to your default restrictions to block all status queries.

Use disable monitor to disable the ``ntpdc -c monlist'' command while still allowing other status queries.

References

CVE Name CVE-2013-5211
FreeBSD Advisory SA-14:02.ntpd
URL http://support.ntp.org/bin/view/Main/SecurityNotice#DRDoS_Amplification_Attack_using