From owner-freebsd-bugs@FreeBSD.ORG Tue Dec 31 17:30:00 2013 Return-Path: Delivered-To: freebsd-bugs@smarthost.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id B86C7FCF for ; Tue, 31 Dec 2013 17:30:00 +0000 (UTC) Received: from freefall.freebsd.org (freefall.freebsd.org [IPv6:2001:1900:2254:206c::16:87]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 934E21226 for ; Tue, 31 Dec 2013 17:30:00 +0000 (UTC) Received: from freefall.freebsd.org (localhost [127.0.0.1]) by freefall.freebsd.org (8.14.7/8.14.7) with ESMTP id rBVHU0Lq021305 for ; Tue, 31 Dec 2013 17:30:00 GMT (envelope-from gnats@freefall.freebsd.org) Received: (from gnats@localhost) by freefall.freebsd.org (8.14.7/8.14.7/Submit) id rBVHU0kE021304; Tue, 31 Dec 2013 17:30:00 GMT (envelope-from gnats) Resent-Date: Tue, 31 Dec 2013 17:30:00 GMT Resent-Message-Id: <201312311730.rBVHU0kE021304@freefall.freebsd.org> Resent-From: FreeBSD-gnats-submit@FreeBSD.org (GNATS Filer) Resent-To: freebsd-bugs@FreeBSD.org Resent-Reply-To: FreeBSD-gnats-submit@FreeBSD.org, Brian Rak Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 4E50BD36 for ; Tue, 31 Dec 2013 17:25:07 +0000 (UTC) Received: from oldred.freebsd.org (oldred.freebsd.org [IPv6:2001:1900:2254:206a::50:4]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 3A79711FF for ; Tue, 31 Dec 2013 17:25:07 +0000 (UTC) Received: from oldred.freebsd.org ([127.0.1.6]) by oldred.freebsd.org (8.14.5/8.14.7) with ESMTP id rBVHP6kg021885 for ; Tue, 31 Dec 2013 17:25:06 GMT (envelope-from nobody@oldred.freebsd.org) Received: (from nobody@localhost) by oldred.freebsd.org (8.14.5/8.14.5/Submit) id rBVHP6dM021874; Tue, 31 Dec 2013 17:25:06 GMT (envelope-from nobody) Message-Id: <201312311725.rBVHP6dM021874@oldred.freebsd.org> Date: Tue, 31 Dec 2013 17:25:06 GMT From: Brian Rak To: freebsd-gnats-submit@FreeBSD.org X-Send-Pr-Version: www-3.1 Subject: misc/185371: NTPD vulnerable to being used for DDOS X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 31 Dec 2013 17:30:00 -0000 >Number: 185371 >Category: misc >Synopsis: NTPD vulnerable to being used for DDOS >Confidential: no >Severity: non-critical >Priority: low >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Tue Dec 31 17:30:00 UTC 2013 >Closed-Date: >Last-Modified: >Originator: Brian Rak >Release: 9.1.0 >Organization: >Environment: FreeBSD XXXX 9.1-RELEASE FreeBSD 9.1-RELEASE #0 r243825: Tue Dec 4 09:23:10 UTC 2012 root@farrell.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC amd64 >Description: The FreeBSD default ntp.conf makes the NTP server vulnerable to being used for a DDOS attack. Please see: http://www.symantec.com/connect/blogs/hackers-spend-christmas-break-launching-large-scale-ntp-reflection-attacks https://isc.sans.edu/diary/NTP+reflection+attack/17300 https://cert.litnet.lt/en/docs/ntp-distributed-reflection-dos-attacks The issue is in this configuration file: http://svnweb.freebsd.org/base/release/9.2.0/etc/ntp.conf?revision=255898&view=markup All the restrict lines are commented out (for reasons I'm unsure of, the comments don't make any sense). >How-To-Repeat: To determine if a server is vulnerable: ntpdc -c monlist SERVERIP If you see a list of hosts, rather then 'timed out, nothing received', the machine can be exploited in this way. >Fix: You can replace all the existing (commented) restrict lines with the following: restrict default kod limited nomodify notrap nopeer noquery restrict -6 default kod limited nomodify notrap nopeer noquery restrict 127.0.0.1 restrict -6 ::1 This configuration will allow the NTP daemon to function correctly both as a client and server, and prevent it from being abused in this way. >Release-Note: >Audit-Trail: >Unformatted: