Are there any crackme sites made for cheat engine or to practice game hacking particularly?

Question

I've checked several crack me sites and they're all on reverse engineering applications.

However, I would like to practice reverse engineering by manipulating game values. The cheat engine tool allows us to do this. There's also a bunch of other tools (ex. tsearch) but cheat engine is the most popular. It involves searching through the RAM for various values, and then manipulating the pointer, creating patches to have permanent effects in memory.

The normal sites aren't a good practice for this because games typically have lots of changing values, especially those that change with user input. Are there any crackme sites which allow me to practice reverse engineering using cheat engine?

Answer 1

TL;DR: (probably) No :(

I'm afraid I don't think there is some site like this, mainly because it is much harder to generate minimal example games for memory manipulation which resemble a real life scenario than in reverse engineering or debugging challenges.

Games are often quiet complex and feature multi threaded gameloops and complex engines which keep track of various property values.

Although there are games meant to be messed with (such as pwnadventure3), I'm afraid examples like these are rare.

I would like to encourage you to make use of the tutorials on youtube. Try to target a game with minimal / no security measures first (single player, maybe indies without a big engine backing them) and try to search for tutorials. When you find one, it will indicate the target (e.g. fix health, enable flying, ...) and you can try to do this yourself without watching the video in the first place. You may watch it afterwards and use it to streamline your workflow. Like with most reverse engineering related tasks, hands on experience is king.

You can always make the computer show you anything you'd like. The real challenge starts with finding vulnerabilities in multiplayer games, because this way your manipulation exceeds the scope of your own system. For example, one of the first things usually checked in game manipulation is whether the server performs sanity checks on manipulateable values such as loot, health etc.

For example, when the server accepts jumping packages from the client and does not check for sanity (e.g. that the character is grounded and didn't jump a millisecond ago) you could abuse this behavior to implement flying. If the game utilizes a thick client structure, it may even trust the coordinates send by the client.

You'll have to explore game functionality and find the loopholes. For example, if a game implements a quick travel system maybe there are checks missing whether you could actually utilize it at any given moment or whether you can just travel to locations which are currently unlocked. Basically there are always two kinds of checks: requests something from the server and show its answer, or disable / change the interface to render the functionality unavailable to the normal user.

At some point, you may even want to mess with anti-cheat systems which check memory sections for manipulation and implement other strategies such as network proxies. There is a nice youtube playlist of LiveOverflow trying to beat pwnadventure this way.

On Game Hacking:

/r/REGames

/r/gamehacks

Answer 2

Your best "crack-mes" for games are games themselves! If spending money on games is a barrier to entry you'd rather not venture, then consider the following:

1. Demo/trial/free-to-play games on Steam. These are all freely available for you to download and work with. There are filters you can toggle to search for these types of games on Steam, so it's easy to find them. Examples: Free to play and free demos.
2. Open-source video games. Once again, these are free games, and they probably more fit the mold of your idea of a game crack-me since they're often somewhat crude/amateur in their artwork. These games have the added benefit of available source code, so you can imagine all the things that are possible if you'd like to dig deeper into specific things!
3. Cheat Engine has two of its own crack-mes built in! One of them is text-based, and the other is graphics-based.
4. As mentioned by Norwald, there are games made to be hacked, such as the PwnAdventure games--all of which (as well as other recommendations) can be found on a game-hacking GitHub repo I personally run.
5. Itch.io is a treasure trove of free-to-play games created by amateur game developers! You'll find games created within all sorts of engines, which will give you some solid exposure to learning many of the differences between, say, Unity, GameMaker, Flash, etc.

There are others, but between those recommendations, you'll have exponentially more options than you could take on even if you wanted to! =)

Finally, if you REALLY get into things, I've been running a game-hacking channel on YouTube for ~5 years now, so there's a lot of fantastic educational material there if you're interested--as well as lots of videos showing you the true power of Cheat Engine and many of its buried features. Check it out sometime if you're so inclined!