Cheat Engine

KimochiYikes · How do I cheat? Reputation: 0 Joined: 26 Dec 2023 Posts: 3

Hi, I was testing createthread on simple commands to add a number. In the end I decided to use the same function the game uses (it uses a special class to store currency).

Enabling the script works as expected, it adds 1000 each second. The problem however is when I turn it off, the game crashes. It still works when I remove the whole first call (the function isn't too complicated nor is it a loop and uses some other simple two sub-functions).

What is interesting though is that sleep before ret doesn't immediately crash the game, which I suspect is my problem. I am not sure how to debug it---

ParkourPenguin · Posted: Tue Dec 26, 2023 12:29 pm Post subject:

KimochiYikes · How do I cheat? Reputation: 0 Joined: 26 Dec 2023 Posts: 3

ParkourPenguin · Posted: Tue Dec 26, 2023 3:23 pm Post subject:

Stacks grow downwards in memory. When you push values onto the stack, you increase the stack size by 4 bytes and subtract 4 from esp. Removing items from the stack entails adding to esp. Specifically, adding 0x14 to esp after the call removes all the items you pushed onto it. `add esp,14` keeps the stack balanced.

"Infinite garbage stack growth" is what you were doing- just pushing values onto the stack endlessly without ever cleaning them up.
When the `ret` instruction is executed, it's suppose to pop the return address from the stack that a `call` instruction pushed on the stack; instead, it pops the garbage you left on the stack and tries to jump there. This is obviously bad.

This doesn't apply to `sleep`. `sleep` is stdcall- a callee-cleanup calling convention. The function being called cleans up the arguments. No need for you to worry about it.

(in 64-bit code, values on the stack are 8 bytes, not 4)

KimochiYikes · How do I cheat? Reputation: 0 Joined: 26 Dec 2023 Posts: 3

Thanks for pointing it out, that should be plenty for me to go on from!