Good day

Direct Link to Advisory
http://homepage.mac.com/adonismac/Advisory/steg/steganography.html

Affected Product

Steganography 1.7.1 and 1.8 (latest). http://www.securekit.com/hidefiles.htm

Bug Type and Date

Type: Bad Design
Date: 01/06/2007

Bug Results

Cracking encrypted steganorgaphy files without any bruteforce.

Bug Description

You can crack steganography encrypted files very easy in fact in less than one minute. The problem is similar to the bug I found in PGP last year.

First you have to identify the steged files. Steganography application leave a footprint after you stego a file.

If you look at the end of your steged file you will notice it will end with 30 00 02 FF FF. So a simple HEX search will reveal all steged files.

So now we have identified the steged, the next step is to access the HIDDEN message without cracking the password. Here is how

Proof-of-Concept

Step 01

1- We use a file cover (carrier file) called "picture_original.jpg"

2- We will hide inside it a message "Hello Adonis"

3- We will use a password "aaaaaa"

4- We generated the steged file we will call it "picture_with_hidden_msg.jpg"

Step02

To access the hidden message WITHOUT the original password "aaaaaa" we will do the followings:

1- We will use any other picture file say "mypicture.jpg"

2- We will hide inside it a message "WHATEVER"

3- We will use a password "a"

4- We generate the steged file we will call it "mypicture_steg.jpg"

5- We will open Both pictures in a hex editor

6- We will replace the last 20 bites of " picture_with_hidden_msg.jpg" with the one from mypicture_steg.jpg

7- Save picture "picture_with_hidden_msg.jpg"

8- Open it using a as password. YES we overwrite the password with something we know.

Simple hein !!!

Peace