~$ Advent of Cyber 2022 - Day 10

Posted on Dec. 10th, 2022. | Est. reading time: 2 minutes

Author:
Unknown
Category:
Red Team: Hack a Game

Question 1

What is the Guard's flag?

First we prompt the guard.

Screenshot of one of the game's input modals.Pick a number, any number!

We then search any register that was equal to the number provided.

Screenshot of the memory search system.I too, have used CheatEngine back in the days.

Once we have the register we bookmark it.

Screenshot of a newly bookmarked register.At least we won't be looking for that agin.

We re-prompt the guard, check the value in the register, throw as-is in python, and it spits out the decimal version.

Screenshot of Python converting an integer.If it works, it ain't stupid.

We enter this version:

Screenshot of one of the game's input modals.lucky guess!

The guard lets us through.

Screenshot of an in-game NPC interaction.Yup, I'm a witch... you got me!

We interact again to obtain the flag:

Screenshot of an in-game NPC interaction.Sure you aren't!

Answer: THM{5_star_Fl4gzzz}

Question 2

What is the Yeti's flag?

This time around we just look at decreasing registers.

A screenshot of register search.That's a lotta registers.

Once we iterate, we have an arbitrarily small amount of registers.

A screenshot of register search.That's considerably less registers.

We freeze it at 100.

A screenshot of register search.TADAAAA, I AM IMMORTAL!!

We survive.

Screenshot of the game.And now we talk to the Yeti.

The Yeti gives us the flag:

Screenshot of an in-game NPC interaction.

Answer: THM{yetiyetiyetiflagflagflag}