Blizzard CTF 2017 – The LichKing Reverse Engineering challenge walkthrough

The Lichking challenge

Challenge demo. Click on the picture to enlarge it.

I created this challenge for the Blizzard 2017 CTF competition that took place on 11/05/2017 in the eSports Arena in Santa Ana, Orange County, CA.
( After the CTF event was over, I decided to release it to public and see who can crack it.

This challenge is inspired by the picture password login feature from Windows 8. When you run the challenge, you will be presented with a picture. Your goal is guess what are the 4 secret coordinates (hidden spots) in the picture that you should be clicking using the correct sequence. Once guessed correctly, a congratulatory message box is displayed. If you fail to guess the right 4 points coordinates, then you will see an error message.

This is a pure reverse engineering puzzle and therefore you won’t find any obfuscation or anti-debugging/reverse engineering tricks whatsoever. In the challenge, I left a bunch of hints to make it easy for others to solve the puzzle. Nonetheless, taking the brute-force approach leads to uncovering the hidden message, however this is not the proper solution I am expecting from participants. Continue reading