Hack This Site! - Stego 1

Description:

Click here to try mission level 1

Level 1



This is an encoded message, the only tip you get is '2 null bytes'

Thank (or blame :P) tiksi for making this challenge

NOTE: There is no encoding error, stop submitting bug reports about it.
 ________________
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Solution:

1. Since this challenge show us a BMP image in front of us, let's take time to look at what's inside the image.
2. I use hexedit to check the image. The only tip we get is '2 null bytes'. So, beyond the BMP file and info header, find the hex value between two '2 null bytes' in BMP content line.

   Here is what we fetched from the image:
   00 00 16 16 17 17 17 16 16 16 16 17 17 16 16 17 17 16 16 17 17 16 17 17 17 16 17 17 16 17 16 16 16 16 17 17 16 16 16 16 17 16 17 17 17 16 16 17 17 16 16 17 17 16 17 17 16 00 00

3. Except the '2 null bytes', 00 00, we convert the 16 and 17 into binary where 16 will be 0 and 17 will be 1. Now we get a binary string who's length equals to 55.

   0011100001100110011011101101000011000010111001100110110

4. We could divided each 8 bits part equal to 1 byte to be transformed into ASCII character. But there must be somewhere missing a '0' or a '1' in the binary string since its length is 55.

   0011100
   0011001
   1001101
   1101101
   0000110
   0001011
   1001100
   110110

5. Each time try to add a 0 in the beginning of a line and use the tool below to convert the binary string into a readable text.

   Tool:
   http://home.paulschou.net/tools/xlate/

6. The answer is the following. (837has6)

   0011100
   0001100
   1100110
   1110110
   1000011
   0000101
   1100110
   0110110