Date: Thu, 19 May 2005 22:18:43 -0700 From: "Ted Mittelstaedt" <tedm@toybox.placo.com> To: "Tim Traver" <tt-list@simplenet.com> Cc: bsd <freebsd-questions@freebsd.org> Subject: RE: PAWS security vulnerability Message-ID: <LOBBIFDAGNMAMLGJJCKNCEIBFBAA.tedm@toybox.placo.com> In-Reply-To: <428CF69E.5050807@simplenet.com>
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Hi Tim,
If you don't have the ability to test out the patch then LEARN!
As the advisory said "no known exploits have been released" I also
noticed that the only 2 vendors listed as implementing a fix were
Cisco and Microsoft. And Microsoft was NOT on the problem list for
ANY of their patched OSs. I would therefore assume that the release
of this so-called vulnerability was carefully timed to take place
AFTER Microsoft had got it's ass covered, to make them look good,
and everyone else look bad. I continue therefore to assume that this
is a political security hole, not an actual security hole.
OpenBSD is well known for knee-jerk reactions to real and supposed
security holes, so it's not surprising they released a patch right away
- of course, little good that did them since this advisory trashed them
anyway. But knee jerk reactions don't always take all variables into
account.
I rewrite their patch because it was simple and easy to apply to the
FreeBSD source - but I did not write the networking code in FreeBSD and
have no idea if it is correct, or if OpenBSD even wrote the fix properly,
or if in fact this is a real vulnerability that anyone needs to be
concerned about. In theory, any flat-key lock can be picked in less
than a minute (I've seen it done that fast, and done it myself somewhat
more slowly) but that does not stop millions of them from being sold
at Home Depot every year. If people went to a different type of lock
that was much harder to pick then the burglar might not break in
by picking the lock - but instead by kicking in the door which has
the side effect of destroying the door and frame, and there's a couple
thousand bucks lost right there fixing that - and if all the burgler
does is steal a $200 TV set, then your better off with the pickable lock.
The point is that any change in the networking code
may have side effects that are worse than the problem.
I posted the patch in order to head off a big long dumbass trashing
discussion, because I suspected you were trolling - but I was willing
to give you the benefit of the doubt. If you were really
concerned - such as if you worked for some company that had some
stick-up-their-ass security officer that was bigger than his britches,
and you had to have a fix RIGHT NOW - then this would have allowed you
to apply the patch to shut up the bigger-than-britches security officer
so you could continue about your business. In the meantime then the
networking and security group could have had discussion about the
PROPER way to handle this. Probably that's this patch, but maybe not.
Now I find what? Well, it surely looks to me like I just spoiled
your troll, so your going to pretend it was no big deal, make a lame-ass
excuse about how you really didn't need the patch anyway and can't
apply it because your incompetent, and fade into the woodwork. I told
you to post the patch and info to the appropriate FreeBSD security lists,
and you aren't the least bit interested in doing what I told you. Why -
because you were only interested in this silly hypothetical PAWS exploit
as long as nobody could say "FreeBSD has a fix, shut up and apply it",
so you can go urinate on the parade here. Now I just handed you a
urinal, and your going to run away and pee on someone else.
I don't want to see a fucking thing more from you unless it's:
"Guys, I DID WHAT I WAS TOLD TO DO and went to the FreeBSD security and
networking
mailing lists and posted what I was given and this is what they said"
If you aren't willing to lift a finger to do that, your a fucking
troll. Don't waste anyone else's time here. Next time you ask for code,
you better check out the going hourly rate for custom programming.
Ted
> -----Original Message-----
> From: owner-freebsd-questions@freebsd.org
> [mailto:owner-freebsd-questions@freebsd.org]On Behalf Of Tim Traver
> Sent: Thursday, May 19, 2005 1:27 PM
> To: Ted Mittelstaedt
> Cc: bsd
> Subject: Re: PAWS security vulnerability
> Importance: Low
>
>
> Ted,
>
> thanks for taking a look at this. I'm not sure I have the ability to
> test out your patch. Maybe someone else on this fine list can ?
>
> But this sounds like a pretty severe DOS issue that seems to be
> relatively simple to implement.
>
> Do you know if the 5.x branch is affected by this as well ?
>
> Tim.
>
>
> Ted Mittelstaedt wrote:
>
> >Hi Tim,
> >
> > Here is a slight mod of the OpenBSD patch for OpenBSD 3.6
> that has been
> >rewritten for FreeBSD 4.11. YMMV If it works I would submit
> it to the
> >FreeBSD
> >security list. The only change I made is OpenBSD defines "tiflags"
> >FreeBSD defines
> >"thflags" I assume they are the same thing. The file is in
> >/usr/src/sys/netinet
> >
> >Turning off the timestamps would be a good way to make your network go
> >slow.
> >
> >*** tcp_input.c.original Thu May 19 11:52:30 2005
> >--- tcp_input.c Thu May 19 12:00:14 2005
> >***************
> >*** 976,984 ****
> >--- 976,992 ----
> > * record the timestamp.
> > * NOTE that the test is modified according
> to the latest
> > * proposal of the tcplw@cray.com list (Braden
> >1993/04/26).
> >+ * NOTE2 additional check added as a result of PAWS
> >vulnerability
> >+ * documented in Cisco security notice
> >cisco-sn-20050518-tcpts
> >+ * from OpenBSD patch for OpenBSD 3.6 015_tcp.patch
> > */
> > if ((to.to_flags & TOF_TS) != 0 &&
> > SEQ_LEQ(th->th_seq, tp->last_ack_sent)) {
> >+ if (SEQ_LEQ(tp->last_ack_sent,
> th->th_seq + tlen
> >+
> >+ ((thflags & (TH_SYN|TH_FIN)) != 0)))
> >+ tp->ts_recent = to.to_tsval;
> >+ else
> >+ tp->ts_recent = 0;
> > tp->ts_recent_age = ticks;
> > tp->ts_recent = to.to_tsval;
> > }
> >
> >Ted
> >
> >
> >
> >>-----Original Message-----
> >>From: owner-freebsd-questions@freebsd.org
> >>[mailto:owner-freebsd-questions@freebsd.org]On Behalf Of Tim Traver
> >>Sent: Thursday, May 19, 2005 10:09 AM
> >>To: bsd
> >>Subject: PAWS security vulnerability
> >>
> >>
> >>Hi all,
> >>
> >>ok, this article was just published about a PAWS TCP DOS
> >>vulnerability,
> >>and lists freeBSD 4.x as affected.
> >>
> >>http://www.securityfocus.com/bid/13676/info/
> >>
> >>Does anyone know how to turn the TCP timestamps off on FreeBSD 4.x ?
> >>
> >>and is 5.4 affected too ?
> >>
> >>Tim.
> >>
> >>_______________________________________________
> >>freebsd-questions@freebsd.org mailing list
> >>http://lists.freebsd.org/mailman/listinfo/freebsd-questions
> >>To unsubscribe, send any mail to
> >>"freebsd-questions-unsubscribe@freebsd.org"
> >>
> >>
> >>
> >
> >
> >
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