From owner-freebsd-security@FreeBSD.ORG Tue May 5 13:32:23 2015 Return-Path: Delivered-To: freebsd-security@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 872D9F28; Tue, 5 May 2015 13:32:23 +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 36ADE12FE; Tue, 5 May 2015 13:32:23 +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 t45DWMsO020612; Tue, 5 May 2015 09:32:22 -0400 (EDT) (envelope-from mike@sentex.net) Message-ID: <5548C65D.5070703@sentex.net> Date: Tue, 05 May 2015 09:32:13 -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: Julian Elischer , "freebsd-security@freebsd.org" Subject: Re: SA-14:19 (Denial of Service in TCP packet processing) and jails issue ? References: <5541560C.5020004@sentex.net> <5547E47A.5040502@sentex.net> <55482F9E.8050701@freebsd.org> In-Reply-To: <55482F9E.8050701@freebsd.org> 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: Tue, 05 May 2015 13:32:23 -0000 On 5/4/2015 10:49 PM, Julian Elischer wrote: >> Anyone have any have any ideas what can be done to mitigate this risk >> if its real, or if its a false positive ? > Firstly I assume you are not talking about a vimage jail? > > It seems unlikely that jailing affects that processing. Does the test > actually try cause the problem to occur? a tcpdump would be really nice. Hi, Just a plain jail. No vimage. It doesnt make sense to me either how the jail / no jail would impact it. I am guessing some sort of false positive as well, but I dont understand the details enough of how the vulnerability works and why there would even be a different result whether its a jail or not, whether real or not. Here is what I did this AM. In the parent, I stopped the jail and I bound sendmail and sshd to the IP 98.159.241.178 and an instance of apache so the same services would be visible on the scan outside the jail and inside. I then ran the scan. It came up clean. I then removed sendmail, sshd and apache from the IP addresses, and started up the jail # sockstat | grep 98.159.241.178 # /usr/local/etc/rc.d/ezjail start scantest.sentex.ca Configuring jails:. Starting jails: scantest.sentex.ca. 0{vinyl6}# sockstat | grep 98.159.241.178 root sendmail 78661 5 tcp4 98.159.241.178:25 *:* www httpd 78659 3 tcp4 98.159.241.178:80 *:* www httpd 78658 3 tcp4 98.159.241.178:80 *:* www httpd 78657 3 tcp4 98.159.241.178:80 *:* www httpd 78656 3 tcp4 98.159.241.178:80 *:* www httpd 78655 3 tcp4 98.159.241.178:80 *:* root httpd 78651 3 tcp4 98.159.241.178:80 *:* root sshd 78646 4 tcp4 98.159.241.178:22 *:* root syslogd 78586 6 udp4 98.159.241.178:514 *:* # and then restarted the scan. Sure enough, it comes up vulnerable. I have placed the 2 pcaps, and the reports in http://www.tancsa.com/jail ---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/