Re: [Full-Disclosure] Bypass of 22 Antivirus software with GDI+ bug exploit Mutations - part 2

[Trog <trog () uncon org>]

On Fri, 2005-03-04 at 15:03 -0600, Andrey Bayora wrote:

> The issue is: only 1 out of 23 tested antivirus software can detect
> malicious JPEG image (after 6 month from the public disclosure date).

Perhaps this fact should have rung some alarm bells in your mind.

> Here is the link to results, JPEG file and my paper (GCIH practical)
> that describes how to create this one:
> http://www.hiddenbit.org/jpeg.htm

I had a look at your supposed JPEG exploit file, bulzano2.jpg,
downloaded from the URL you supplied above, and read the 84 page PDF
you've generated to explain your processes.

You appear to have made an error.

The segments of a JPEG file are chained together. In bulzano2.jpg, the
chain goes as follows:

Offset Marker Size Comment
--------------------------

0x0000 FFDB        Start of image marker
0x0002 FFE0   0010 JFIF APP0 marker: next in chain = 0x0004
+0x0010=0x0014
0x0014 FFED   191c APP marker: next in chain = 0x0016+0x191c=0x1932

According to your paper you've added your exploit at offset 0x0210,
which is in the middle of the APP segment that ranges from 0x0018 to
0x1932, as such this is not a valid exploit. The data at 0x0210 may look
like a segment marker, but isn't.

Please explain if I have missed something.

-trog

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