lkml.org 
[lkml]   [2001]   [Nov]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Subjecttest SYN cookies (was Re: SYN cookies security bugfix?)
From
Date
Alan Cox <alan@lxorguk.ukuu.org.uk> writes:

> > I received a forwarded message from SuSE regarding a security vulnerability
> > with respect to randomization of the ISN for SYN cookies - or something to
> > that effect. I have not been able to find the patch which addresses this
> > problem; if anyone can point me towards it, I would be appreciative.
>
> Its fixed in 2.2.20, you can grab the 2.2 patch from there

What is a good way to test SYN cookies? I can induce a three-second
delay (on victim host V) before new TCP connections are accepted by
sending a burst of 2000 SYN packets (from attacker A), where V is
running a 2.2.14 or 2.2.17 kernel. During the three seconds ICMP echo
requests from A to V are being answered.

Turning on SYN cookies after /proc is mounted does not affect the
three-second pause, though, so I figure that either the pause is not
on account of a full half-open connection queue or SYN cookies are not
working.

--
--Ed Cashin PGP public key:
ecashin@terry.uga.edu http://www.terry.uga.edu/~ecashin/pgp/

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:13    [W:0.058 / U:7.700 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site