Rock, Paper, Psychic

Do you want to play a game?

You can see the basic flow of the game above. You put in your choice, then after some calculation the game chooses, and what do you know - the game always makes the winning choice.

How about a nice game of Chess?

Having played the game a couple times to get familiar with the flow, I ran the program using x64dbg.

Hit F9 a few times until it the program gets to your input choice.

Once you’ve typed in your selection in the command window, back to x64dbg. From here we will step over (F8) the instructions 1 by one.

Continue to hit F8 , observing as the rest of the game text appears.

Global Thermonuclear War

In x64dbg, we see that the program tests 2 values and then does a JNE (Jump if not Equal) command to another function 416C6A.

If we use the debugger and change this to JE (Jump if equal to):

Who you calling cheater?

Use the tag #HuntressCTF on BakerStreetForensics.com to see all related posts and solutions for the 2023 Huntress CTF.