Thursday, May 30, 2013

Hack.Lu CTF 2010 : Like skies that are so blue

Hack.Lu CTF 2010 : Like skies that are so blue

Hints given to us:
Sometime even pirates have a lazy sunday...

download - Since the original image is missing, i've uploaded a mirror copy of it here.

gold: 100 +3 (1st), +2 (2nd), +1 (3rd)

Recommended Tools:
1. Any photo editor
2. Brains

Logic behind this:
Initially, i wasted too much time trying to get all sort of tools to see whether is it using any steganography in it. I even checked the meta-data and properties of this file but no success.

But after some thoughts, since it's just a 100 points should not be too difficult right?

Could it be like those old Defcon challenge that the MD5 of the file is the key?
Bingo, the MD5, 032c49411912397eea2a7d906dab5f7e, of the image file is the answer.

Now that i've accidentally solve this. But there must be something to in the image that give this clue to me.
After spending some more time on it, it seems like if you fill the image with another colour( i used Black this time round as it's default in most image editors).

You will see the following image, which is the essential clue. :P

Hooray, challenge completed. :D


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