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Re: Microsoft Windows image rendering DoS vuln

From: patrick <mccpat () gmail com>
Date: Wed, 20 Apr 2005 18:01:29 +0000
Andrew wrote:


                  Alpha-Pi-Omicron Pi-Alpha-Nu-Tau-Omicron-C?
     Kappa-Alpha-Kappa-Omicron-Delta-Alpha-Iota-Mu-Omicron-Nu-Omicron-C?
  __    ___  __ _____         _       _        
___                       _ _
 / /   /___\/ // _  /   /\  /(_) __ _| |__     / __\___  _   _ _ __  
___(_) |
/ /   //  // / \// /   / /_/ / |/ _` | '_ \   / /  / _ \| | | | '_ \ /
__| | |
/ /___/ \_// /___/ //\ / __  /| | (_| | | | | / /__| (_) | |_| | | | |
(__| | |
\____/\___/\____/____/ \/ /_/ |_|\__, |_| |_| \____/\___/ \__,_|_|
|_|\___|_|_|
                               
|___/                                        
Overview

There exists a vulnerabilility in the way Microsoft Windows handles
the rendering
of images. By resizing an image with html properties to an extremely
large size an
attacker may perform a very quick and effective denial of service
attack upon a
victim.


I. Description and PoC

Only clients running Internet Explorer, Firefox, or Avant in Windows
2k or XP have
been confirmed to be vulnerable. Opera does it's own image rendering
and is not
ulnerable to this method of attack. The status of Longhorn is not
known. Other
operating systems, including Mac OS X and Linux are not vulnerable.

You may point your browser to this URL to see a live demonstration of
this attack:

http://www.livejournal.com/users/deeplolz

This may cause an instant reboot or bluescreen detailing a problem
with your video
drivers. Other possibilities include an extended period of poor
performance until
next reboot, a short to medium period of nonfunctionality or a crash
of the
browser.


II. Impact

Because this attack can be performed anywhere an img src is allowed,
there are
many forums including blogs, messageboards, and others which are
vulnerable. It
is hopeful that Microsoft will release a patch for this attack as soon as
possible.


III. Solution

Until a patch is released you are advised to use the Opera web
browser. It might
also be possible to write a script for the Firefox "GreaseMonkey"
extension which
performs a workaround for this attack. Such as setting height and
width of images
to 5000 pixels if they are currently set to render at over 5000.


Very special shouts: Girlvinyl, Hepkitten, Confkids, and Frienditto
(Come back!!!
We need you badly, FD!)

Shouts:
LJD, LJ-Zeera, Encyclopedia Dramatica, Lulz News Network, Project
Mayhem, Amalea,
Wednesday Night Karate Explosion, The Gundanium Alloys Manufacturers
Association,
Richmond Flash Mob Society, RVA_BS, RVA_FYAD, Brad Fitzpatrick, Mena
Trott, SALJ,
The International Department of Internet Security, #telconinjas,
undernet #drugs,
The Kadaitcha Dancers, psychotic vegans, Warren Ellis, and pro-ana
preteen girls.


Hmm, a few things.

1) That site is down. Has been down ever since I got this email.
2) I created a site with this HTML code:

/././././././././././././

<html>
<body>
<p>If you are using IE, YOU SUCK! Just kidding.<br>
If you're in Window$ though, this should crash your puter<br>
or give you a BSOD. HAVE FUN BUDDY! MUA HA HA!</p>

<img src="http://thepcelement.com/hardware/neowinscreenie.jpg";
height="9999999999999999999999999999999999999999999999999991"
width="999999999999999999999999999999999999999999999999999999999999999991">

</body>
</html>

/./././././././././././

Yet no crash, this was on my Dad's PC running Window$ XP, no SP2,
Firefox and Internet Exploder, the image was all white, no slowdown or
anything.

Can you tell me what I'm doing wrong and give me the source to that page
you had up as a live demonstration? I'm interested to see more about
this vulnerability.

Thanks for posting, have a nice day,
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