Game cheating has existed almost as long as multiplayer games themselves. What most players see as a simple unfair advantage is, under the hood, a surprisingly sophisticated piece of software engineering. This article takes a technical deep-dive into how Counter-Strike2 (CS2) cheats are built, covering the architecture of internal cheats, how the Source2 SDK is leveraged and how functions could be hooked at runtime.
Introduction
The original idea for making a game cheat came from wondering about how the in-game bullets impact my character. I thought that the game must know where both the enemy player and I are and calculate the path of the bullet and apply damage to the health.
So, after that, I looked up how a game is programmed and how the process for it works. After investigating and understanding the basics of how a game works under the hood, I got redirected to a forum where people shared ideas and concepts of video game cheating. That was the place where I learnt about how cheats exploit the functionalities of games and realised that the concepts themselves were easy enough to understand. Hence, I wanted to see how hard it was to create a cheat myself, so I created both an external and internal cheat; however, only the internal implementation will be covered in this post.
Reverse Engineering
No matter the type of cheat one would like to create, everything starts with reverse engineering. The idea is simple enough: decompile a DLL and look for the instructions that are needed. However, in real life this is a bit more complicated.
Disassemblers like IDA, Ghidra, or x64dbg turn machine code back into assembly, but assembly alone rarely explains what’s going on. Static analysis means reading through the code without running it, tracing function calls and spotting patterns like loops or conditionals. Dynamic analysis means running the program under a debugger and setting breakpoints to watch register and memory values in real time. Combining both builds a working picture of what the code does. Cross-referencing strings and known API calls is often the fastest shortcut, since a call to something like CreateFileW narrows down a routine’s purpose far quicker than reading raw assembly. Ghidra’s pseudo-C decompiler view also helps, turning much of that raw assembly into something closer to readable code.
What Makes a Game “Hackable”?
Before diving into the cheat mechanics, it helps to understand what a game actually exposes at a fundamental level. Every game, CS2 included, is built around a set of core primitives as mentioned in the Introduction:
Characters
- Move
- See and be seen
- Hear and be heard
- Shoot, and interact with the environment.
Objects
- Interactable (a gun that fires, a door that opens) or manipulatable
- Carrying state that changes, like a bomb going from unarmed to armed.
These primitives are the attack surface. Every piece of information the game needs to function, player positions, health values, view angles, recoil vectors, has to live somewhere in memory. And if it lives in memory, it can be read. If it can be read, it can be modified.
External vs Internal Cheats
There are two fundamental approaches to building a game cheat, and the distinction matters enormously for how they’re built, detected, and defeated.
External cheats run as a completely separate process alongside the game, reading and writing the game’s memory from the outside using Windows APIs like ReadProcessMemory and WriteProcessMemory. An example could be reading a player’s health value or writing a new view angle to redirect where the player is looking. The advantage is that the cheat process never touches the game’s process space. The downside is that it’s easier for anti-cheat to detect a process making suspicious memory access calls to the game.
Internal cheats work very differently. Instead of reading from outside, they inject a Dynamic Link Library (DLL) directly into the game’s process. Once injected, the cheat code runs inside the same process as the game itself, same memory space at the same privilege level. This opens up a much more powerful technique: hooking. By intercepting and redirecting function calls inside the game, internal cheats can run arbitrary code at precisely the right moment in the game’s execution loop. The project covered in this post is a Proof-of-Concept (PoC) internal cheat, a DLL injected into CS2’s process. Some parts of the project have been redacted or completely left out of this post to preserve the integrity of the game and the engine on which it runs.
Different functionalities are not always compiled into the same libraries or DLLs, so it takes some research to determine which one is needed for a given function that must be implemented. This can be done in two ways: by checking forums to see if others have already identified which DLL contains a specific functionality, or by reverse engineering the binaries and searching for the relevant class or function name. It is, however, commonly known that different DLLs contain different specific functions. Just a few examples below:
- client.dll — Manages client-side game logic, entities, and prediction.
- engine2.dll — Controls the core Source 2 game loop, server connections, and state.
The Source2 SDK: Interfaces and Schemas
CS2 runs on Valve’s Source2 engine, and the engine exposes its internal structure through two key concepts that cheat developers exploit heavily: Interfaces and Schemas.
Interfaces
An Interface is a class extracted from CS2’s DLL files, each managing a specific domain of game functionality. Each interface stores its functions in a vtable, a standard C++ mechanism where function pointers are stored sequentially in memory.
To get an interface, the cheat locates DLLs exported via the CreateInterface function by process address, calls it with the interface name (or finds it via pattern scanning), and returns a pointer to the interface object. From there, the cheat can call any function the interface exposes or hook those functions to intercept them.
Schemas
Schemas are how Source2 stores structured data about game objects. A schema entry has three parts, a class name, a property name, and an offset.
The SchemaSystem itself is a Source2 interface, so accessing it requires getting the in-game SchemaSystem interface, implementing a method to query schemas (partially borrowed from existing community implementations), and creating a custom getter to retrieve schema values by class and property name. Once the schema system is wired up, the cheat can read real, live values from any game object, a player’s health, their position, their glow state, smoke grenade colours, all by querying the schema with the right class and property name, then reading at the returned offset.
One important nuance:
In CS2, each player entity (called a “pawn” or “player”) is wrapped in approximately five layers of class inheritance. Some values are stored in layer 2, others in layer 5. Traversing that inheritance chain correctly is essential for reading the right data.
Said Schemas could contain the following values:
Figure 1 – Player Health
Figure 2 – Player Glow
Figure 3 – Smoke Colour
Trampoline Hooking: Hijacking Execution Flow
The core technique that makes internal cheats so powerful is trampoline hooking. The concept is to locate a target function in memory, then overwrite the instructions at its entry point with a jump that redirects execution to the cheat’s own implementation. You can’t overwrite half an instruction, so you replace whole instructions, enough of them to make room for the jump, which usually means clobbering slightly more than the jump alone needs. Those overwritten instructions are real code from the function’s prologue, so the hook relocates them into a small trampoline stub. To let the game run normally, the cheat calls the trampoline, which executes the saved instructions and then jumps back into the original function just past the patched region, not to its start (returning to the start would re-trigger the hook forever). The original appears to execute as intended, the game never knows it was intercepted, and the cheat gets to inspect and modify every argument first.
The saved prologue bytes live in the trampoline; the cheat resumes the original past the patched bytes to avoid an infinite loop.
Figure 4 – Trampoline Hook
Anti-Cheats and Protections
Most games, just like CS2, protect against cheaters by using Anti-Cheat software.
CS2 uses Valve’s own AC called VAC. VAC in CS2 is really two linked systems. The original VAC is a client-side signature scanner: it checks files and processes on your machine when you connect to a VAC-secured server and bans you if it recognises known cheat software. These bans are permanent and cannot be appealed or removed by Steam Support, though Valve doesn’t ban on reports alone.
Alongside it sits VACnet, a server-side, behavioural system. Rather than checking what’s installed, it analyses how a player behaves, since cheats can hide from a signature scan far more easily than they can hide the shape of their aim. It uses neural networks and deep learning to assess movement, aim patterns and network behaviour in real time. The current version, VACnet 3.0, includes VAC Live, which can end a match immediately and ban a player mid-round if it detects high-confidence cheating like rage hacking or anti-aim, with no rating lost for teammates. There’s also an Overwatch layer where trusted reviewers check flagged demos, and the system can now catch hardware-assisted input automation, resulting in a kick rather than a ban.
However, it isn’t perfect. For example, Valve reversed a couple of mistaken ban waves, and in July 2026 fixed a VACnet bypass that had allowed some rage cheaters to slip past behavioural analysis entirely.
Closing Thoughts
Building a game cheat at this level is a genuine exercise in reverse engineering, C++ internals, Windows memory management, and real-time mathematics. It requires understanding how a game engine renders and tracks entities in memory, how to intercept or manipulate that data without crashing the process, and how to do all of this quickly enough to keep pace with a match running at well over a hundred frames a second. Layered on top of that is the constant pressure of evasion: anything that touches memory, hooks a function, or injects code risks being fingerprinted by anti-cheat systems, so cheat developers are effectively running their own arms race against Valve’s detection models. It’s a demanding technical pursuit, even if the end goal undermines the fairness of the game itself.
