How do I use a game's base pointer to edit a value in C++?

Question

Okay I've followed a couple of tutorials on how to find the base/static pointer of a game's value with cheat engine (hp, strength, experience, gold, etc). To test this I tried it on Microsoft's Spider Solitaire and it worked. I got the base pointer for the amount of moves ("zetten" as you will see in my dutch version of Spider Solitaire), and made it reference to another pointer which referenced to the actual value (assuming that's how it's called).

That's basically what it looks like. So now I've got the base pointer which would be SpiderSolitaire.exe+B5F78 and it uses 2 offsets to get to the actual address of the value. This is the code that I use to edit memory values with in C++:

#include "stdafx.h"
#include <iostream>
#include <Windows.h>
#include <strsafe.h>

using namespace std;
int _tmain(int argc, _TCHAR* argv[])
{

    long address = 0x??????;
    int newvalue = 200000; 
    DWORD newvaluesize = sizeof(newvalue);

    HWND hWnd = FindWindow(0, L"Spider Solitaire");
    HANDLE pHandle; 
    DWORD pid; 

    if(hWnd != 0) { 
        cout << "Found windowx.\n"; 
        GetWindowThreadProcessId(hWnd, &pid);
        pHandle = OpenProcess(PROCESS_ALL_ACCESS, FALSE, pid); 
    } 
    else {
        cout << "Can't find window\n";
    } 
    if(pHandle !=0) { 
        WriteProcessMemory(pHandle, (LPVOID)address, &newvalue, newvaluesize, 0);   
        cout << "Written to memory successfully\n";
        getchar();
    } 
    else { 
        cout << "Couldn't get handle.\n";
        getchar();
    } 
    CloseHandle(pHandle);
    return 0;
}

So I have all the information I need, except I don't know how to implement base pointers and offsets and whatnot into the C++ program. I tried using

long address = SpiderSolitaire.exe+B5F78+e8+10

but that didn't work (SpiderSoliteire.exe is a string anyway so I didn't expect it to work). I've tried searching for tutorials or something on the internet, but those only show how to directly alter a value in 1 memory address, not how to alter a value by referencing it through 2 pointers. How do I do this? How do I implement this base pointer, and the 2 offsets into my C++ program so that I can edit the memory value?

score 0 · Answer 1 · answered Jul 19 '12 at 14:49

0

I tried same thing and they said to that i need to write my own OS for that. Some said i need to be in ring-0 area. I say you can use asm (assembler)

 mov [address],register

comand

Gcc, VC++ 10 , Digital Mars has some asm{} block definitions inside.

answered Jul 19 '12 at 14:49

huseyin tugrul buyukisik

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I think you might have misunderstood my question. I already have the base address, and the 2 offsets. All I need to do is figure out how to put those into C++ so I can write to the correct address. – ZimZim Jul 19 '12 at 14:52
i didnt say to get address. i showed you to how to write to address – huseyin tugrul buyukisik Jul 19 '12 at 14:56
This answer indeed doesn't make sense. You can't write to another process with `mov`, not even in assembly. – MSalters Jul 19 '12 at 14:56
does windows check every mov instruction to see if it is illegal? – huseyin tugrul buyukisik Jul 19 '12 at 15:01
if windows is checking every assembly instruction, then it is not even pure assembly. – huseyin tugrul buyukisik Jul 19 '12 at 15:02
@tuğrulbüyükışık: Windows doesn't check, your CPU does. In particular, the CPU's MMU does. Each process has its own virtual-to-physical mapping. – MSalters Jul 19 '12 at 15:05
BTW, the "Write your own OS" was in regard to your question how you'd read _any_ byte. Some bytes do not belong to any process, but the OS itself. Therefore these bytes can only be read by that OS. `ReadProcessMemory` is a valid Windows method to read bytes from other processes, and therefore can't read _all_ bytes. – MSalters Jul 19 '12 at 16:14
mmu? a secret register? can i reach that? – huseyin tugrul buyukisik Jul 19 '12 at 16:20
how can i cancel the cpu's breakpoint system to let my program freely execulte mov [xxxx],y instruction – huseyin tugrul buyukisik Jul 19 '12 at 16:21

score 0 · Answer 2 · edited May 23 '17 at 12:30

0

You have to figure out where the process is loaded, which can vary. See this earlier question for details. It does more than you need; you just need the base address part.

edited May 23 '17 at 12:30

Community

1
1

answered Jul 19 '12 at 15:03

MSalters

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How do I use a game's base pointer to edit a value in C++?

2 Answers2