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c++memory-access

Accessing Memory of other applications C++

I am thinking about a problem I have been having for some time now.. I would like to write a C/C++ program (under windows first) that can access(read/change values) the memory(stack, heap, everything) of other running programs. (Not like shared memory but any memory the computer has..) Without having to start the application from my own application.. I have seen something like this before but I just can't figure out how it's done.. If I were to access the memory of any running program I would get errors from the OS right? Any help is appreciated!

Solution

  • As @sharptooth said, this requires support from the OS. Different OS does it differently. Since you are on Windows, there are a few steps you could follow:

    1. Call OpenProcess, or CreateProcess to access, or launch a new process. In this call, you must request PROCESS_VM_READ access.
    2. Call ReadProcessMemory to read a chunk of memory in that opened process.

    If you want to change memory of another process, you then need PROCESS_VM_WRITE access and use WriteProcessMemory to achieve that.

    In Linux, for example, you'd use ptrace to attach to a process and peek, poke its memory.