These run as a separate process outside of the game. They use system calls like ReadProcessMemory and WriteProcessMemory to interact with the game's data. While often safer from certain detection methods, they are generally less performant than internal versions. Core Components of Cheat Source Code
Code for finding the game's window handle ( HWND ) and process ID to gain access to game memory.
The development and usage of source code for cheats is a complex intersection of software engineering, reverse engineering, and game security. Types of CS:GO Cheat Architectures