Date: Mon, 04 May 2015 17:28:26 -0400 From: Mike Tancsa <mike@sentex.net> To: "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: <5547E47A.5040502@sentex.net> In-Reply-To: <5541560C.5020004@sentex.net> References: <5541560C.5020004@sentex.net>
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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/
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