Re: [Unpatched] New 0day exploit for XPSP2

[Juergen Schmidt <ju () heisec de>]

On Wed, 20 Oct 2004, Thor Larholm wrote:

Hello Thor,

> When
> IE renders an IMG element it gives priority to the SRC attribute but
> when IE drops an IMG element on an arbitrary window it gives priority to
> the DYNSRC attribute. If you are able to reference any local content you
> can therefore drop the DYNSRC attribute of the IMG element on the window
> with local content and thereby plant a file on the file system in a
> known location.

Sorry that I do not understand your very interesting explanations.
I examined http-equivs demo, but he isn't using the DYNSRC attribute
anywhere near the drag&drop part.

The only file containing "dynsrc" is his pseudo database foobar.txt, which
is used in the last stage of the exploit, to download "code".

His drop source is included with a simple

<img src="malwarez"  width="30" height="30" style="cursor:hand" title="drag me!">

Absolutely no DYNSRC here.

So the question stays: malwarez carries no extension, it is a valid GIF
image, but when it is dropped, it is named "malwarez[1].htm"
The only explanation I have, is that the server declares
malwarez to be HTML:

# wget -S http://www.malware.com/malwarez
--18:41:25--  http://www.malware.com/malwarez
           => `malwarez'
 1 HTTP/1.0 200 OK
 ...
 8 Content-Type: text/html
                      ^^^^

So IE just uses the Content-Type to name this file.


bye, ju

--
Juergen Schmidt    Chefredakteur  heise Security   www.heisec.de
Heise Zeitschriften Verlag,  Helstorferstr. 7,  D-30625 Hannover
Tel. +49 511 5352 300 FAX +49 511 5352 417    EMail ju () heisec de

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