// (c) Code By Extreme
// Description:Ring3 Api hook engine(by EAT)
// Last update:2010-4-16

#include <stdio.h>
#include <conio.h>
#include <windows.h>
#include <tlhelp32.h>

HANDLE WINAPI MyOpenProcess( DWORD dwDesiredAccess, BOOL bInheritHandle, DWORD dwProcessId)
{
    MessageBox(NULL, "Call!", "wonderful!", 0);
}

DWORD GetDllBaseAddr(char *DllName)
{
    HANDLE hToolHelp;
    MODULEENTRY32 ModEntry;    
    
    hToolHelp = CreateToolhelp32Snapshot(TH32CS_SNAPMODULE, GetCurrentProcessId());
    if (hToolHelp == INVALID_HANDLE_VALUE)
    {
        return 0;
    }
    
    if (!Module32First(hToolHelp, &ModEntry))
    {
        return 0;
    }
    
    while (Module32Next(hToolHelp, &ModEntry))
    {
        if (!strcmp(ModEntry.szModule, DllName))
        {
            CloseHandle(hToolHelp);
            return (DWORD)ModEntry.modBaseAddr;
        }
        
    }
    
    return 0;
    CloseHandle(hToolHelp);
    
}

PVOID GetEAT(char *DllName, char *ExpName)
{
    PVOID Pointer;
    DWORD DllBaseAddr;
    PIMAGE_EXPORT_DIRECTORY ExpDir;
    
    PDWORD AddrOfNames;
    PDWORD AddrOfFuncs;
    PUSHORT AddrOfOrdinals;
    
    DWORD Cnt;
    DWORD Max;
    PDWORD AddrToWrite;
    DWORD dwTmp; 
    BYTE DataToWrite[4];

    DllBaseAddr = GetDllBaseAddr(DllName);
    if (DllBaseAddr == 0)
    {
        return 0;
    }
    
    // IMAGE_DOS_HEADER
    Pointer = (PVOID)DllBaseAddr;
    if (Pointer == 0)
    {
        return 0;
    }
    
    // IMAGE_NT_HEADERS
    Pointer = (PVOID)((DWORD)((PIMAGE_DOS_HEADER)Pointer)->e_lfanew + DllBaseAddr);
    if (Pointer == 0)
    {
        return 0;
    }
    // IMAGE_EXPORT_DIRECTORY
    ExpDir = (PIMAGE_EXPORT_DIRECTORY)((DWORD)(((PIMAGE_NT_HEADERS)(Pointer))->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress) + DllBaseAddr);
    AddrOfNames = (PDWORD)((DWORD)ExpDir->AddressOfNames + DllBaseAddr);
    AddrOfFuncs = (PDWORD)((DWORD)ExpDir->AddressOfFunctions + DllBaseAddr);
    AddrOfOrdinals = (PWORD)((DWORD)ExpDir->AddressOfNameOrdinals + DllBaseAddr);
    
    Max = ExpDir->NumberOfNames;
    for (Cnt = 0; Cnt < Max; ++Cnt)
    {
        if (!strcmp((PUCHAR)(AddrOfNames[Cnt] + DllBaseAddr), ExpName))
        {
            dwTmp = (DWORD)MyOpenProcess - DllBaseAddr;
            memcpy(DataToWrite, &dwTmp, sizeof(DWORD));
            AddrToWrite = &AddrOfFuncs[AddrOfOrdinals[Cnt]];
            if (!VirtualProtect(AddrToWrite, sizeof(DWORD), PAGE_EXECUTE_READWRITE, &dwTmp))
            {
                return 0;
            }
            
            WriteProcessMemory(GetCurrentProcess(), (PDWORD)AddrToWrite, DataToWrite, sizeof(DWORD), &dwTmp);
            if (dwTmp != sizeof(DWORD))
            {
                return 0;
            }
            return 0;
        }
    }
    return 0;
}

int main()
{
    PVOID Addr;
    Addr = GetEAT("kernel32.dll", "OpenProcess");
    Addr = (DWORD)OpenProcess;
    return 0;
}

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