Date: Tue, 05 May 2015 10:49:02 +0800 From: Julian Elischer <julian@freebsd.org> To: Mike Tancsa <mike@sentex.net>, "freebsd-security@freebsd.org" <freebsd-security@freebsd.org> Subject: Re: SA-14:19 (Denial of Service in TCP packet processing) and jails issue ? Message-ID: <55482F9E.8050701@freebsd.org> In-Reply-To: <5547E47A.5040502@sentex.net> References: <5541560C.5020004@sentex.net> <5547E47A.5040502@sentex.net>
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On 5/5/15 5:28 AM, Mike Tancsa wrote: > 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 ? 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. > > 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 > > >
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