c++ - 从正在运行的进程中注入(inject) DLL 后弹出

Question

我写了这个函数来将 DLL 注入(inject)到正在运行的进程中:

DLL_Results CDLL_Loader::InjectDll()
{
    DWORD ThreadTeminationStatus;
    LPVOID VirtualMem;
    HANDLE hProcess, hRemoteThread;
    HMODULE hModule;

    if (!isInit())
        return NOT_INIT;

    if (isInjected())
        return DLL_ALREADY_HOOKED;

    hProcess = OpenProcess(PROCESS_ALL_ACCESS, FALSE, ProcessID);
    if (hProcess == NULL)
        return PROCESS_ERROR_OPEN;

    VirtualMem = VirtualAllocEx (hProcess, NULL, strlen(DllFilePath), MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
    if (VirtualMem == NULL)
        return PROCESS_ERRORR_VALLOC;

    if (WriteProcessMemory(hProcess, (LPVOID)VirtualMem, DllFilePath, strlen(DllFilePath), NULL) == 0)
    {
        VirtualFreeEx(hProcess, NULL, (size_t)strlen(DllFilePath), MEM_RESERVE|MEM_COMMIT);
        CloseHandle(hProcess); 
        return PROCESS_ERROR_WRITE;
    }

    hModule = GetModuleHandle(L"kernel32.dll");
    hRemoteThread = CreateRemoteThread(hProcess, NULL, 0, 
                        (LPTHREAD_START_ROUTINE)GetProcAddress(hModule, "LoadLibraryA"),
                          (LPVOID)VirtualMem, 0, NULL);

    if (hRemoteThread == NULL)
    {
        FreeLibrary(hModule);
        VirtualFreeEx(hProcess, NULL, (size_t)strlen(DllFilePath), MEM_RESERVE | MEM_COMMIT);
        CloseHandle(hProcess); 
        return PROCESS_ERROR_CREATE_RTHREAD;
    }

    WaitForSingleObject(hRemoteThread, INFINITE);
    GetExitCodeThread(hRemoteThread, &ThreadTeminationStatus);
    FreeLibrary(hModule);

    VirtualFreeEx(hProcess, NULL, (size_t)strlen(DllFilePath), MEM_RESERVE | MEM_COMMIT);
    CloseHandle(hRemoteThread);
    CloseHandle(hProcess); 
    injected = true;
    return DLLHOOK_OK;
}

它工作得很好，但是当我试图弹出 dll 时，我无法找到关于 unhooking 的信息。我试图构建一些函数来完成它，我想我已经接近这是我到目前为止所得到的:

这是正确的方法吗？如果是这样，我应该在 VirtualMem 的 createRemoteThread instade 中传递什么参数(在注入(inject)函数中使用)...

DLL_Results CDLL_Loader::EjectDll()
{
    DWORD ThreadTeminationStatus;
    HANDLE hProcess, hRemoteThread;
    HMODULE hModule;

    if (isInjected())
        return DLLEJECT_OK;

    hProcess = OpenProcess(PROCESS_ALL_ACCESS, FALSE, ProcessID);
    if (hProcess == NULL)
        return PROCESS_ERROR_OPEN;

    hModule = GetModuleHandle(L"kernel32.dll");
    hRemoteThread = CreateRemoteThread(hProcess, NULL, 0, 
                        (LPTHREAD_START_ROUTINE)GetProcAddress(hModule, "FreeLibrary"),
                          /*(LPVOID)VirtualMem <- What do i need to send here?*/, 0, NULL);

    if (hRemoteThread != NULL)
    {
        WaitForSingleObject(hRemoteThread, INFINITE);
        GetExitCodeThread(hRemoteThread, &ThreadTeminationStatus);
    }

    CloseHandle(hRemoteThread);
    CloseHandle(hProcess); 
    injected = false;
    return DLLEJECT_OK;
}

Answer 1

在 32 位系统上，GetExitCodeThread 之后的 ThreadTeminationStatus 的值包含远程进程中 LoadLibraryA 的返回值。这是新加载的 dll 的模块句柄。您可以将它用作远程线程中 FreeLibrary 的参数。

如果您想在 64 位 Windows 上使用该代码，线程退出代码将被截断为 32 位 DWORD，因此无法使用。您必须在远程进程中创建一个可调用例程(如 Necrolis 所建议的那样)或求助于通过 psapi 或 Toolhelp 查找 DLL 的模块库API(CreateToolhelp32Snapshot、Module32First、Module32Next)。