From owner-freebsd-security@FreeBSD.ORG Mon May 4 21:28:34 2015 Return-Path: Delivered-To: freebsd-security@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id D6324E25 for ; Mon, 4 May 2015 21:28:34 +0000 (UTC) Received: from smarthost1.sentex.ca (smarthost1.sentex.ca [IPv6:2607:f3e0:0:1::12]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (Client CN "smarthost.sentex.ca", Issuer "smarthost.sentex.ca" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id A1825182F for ; Mon, 4 May 2015 21:28:34 +0000 (UTC) Received: from [IPv6:2607:f3e0:0:4:f025:8813:7603:7e4a] (saphire3.sentex.ca [IPv6:2607:f3e0:0:4:f025:8813:7603:7e4a]) by smarthost1.sentex.ca (8.14.9/8.14.9) with ESMTP id t44LSX34033684; Mon, 4 May 2015 17:28:33 -0400 (EDT) (envelope-from mike@sentex.net) Message-ID: <5547E47A.5040502@sentex.net> Date: Mon, 04 May 2015 17:28:26 -0400 From: Mike Tancsa Organization: Sentex Communications User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: "freebsd-security@freebsd.org" Subject: Re: SA-14:19 (Denial of Service in TCP packet processing) and jails issue ? References: <5541560C.5020004@sentex.net> In-Reply-To: <5541560C.5020004@sentex.net> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-security@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: "Security issues \[members-only posting\]" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 04 May 2015 21:28:34 -0000 On 4/29/2015 6:07 PM, Mike Tancsa wrote: > > The IP being scanned is in a jail. If I run the scan to an IP not > associated with the jail, the scan does not complain. Its only on the > jailed IP that the scan flags as problematic for this vulnerability. > > If this is a false positive, how can I be sure thats the case ? I have > pcaps of the scan both against the jailed IP (with the scan saying its > vulnerable) and against an IP not associated with the jail, saying its > not an issue. > Anyone have any have any ideas what can be done to mitigate this risk if its real, or if its a false positive ? To further clarify/describe my test environment, this is a RELENG_9 box I am testing against. I have a number of IPs aliased to lo0 associated with jails. If I run the Qualsys scan against an IP on this box that is not associated with a jail, it passes the test for SA-14:19. If I run the test against an IP associated with the jail, it fails the test. e.g. IP 192.168.1.1 is aliased to lo0 and associated with jail1.sentex.ca. If I run the free qualsys scan against jail1.sentex.ca, the test fails. If I stop the jail, and run the qualsys scan against the same IP, which is now just an aliased IP on the host machine, it passes the test. I have the pcaps, but I am not sure exactly what I am looking for in the data. The test just says it confirmed the vulnerability with the following 2 tests, Tested on port 22 with an injected SYN/RST offset by 16 bytes. Tested on port 25 with an injected SYN/RST offset by 16 bytes. What is it about the jail that might be causing either this issue to resurface, or give a false positive that its an issue ? ---Mike -- ------------------- Mike Tancsa, tel +1 519 651 3400 Sentex Communications, mike@sentex.net Providing Internet services since 1994 www.sentex.net Cambridge, Ontario Canada http://www.tancsa.com/