通过CreateRemoteThread注入DLL

DLL injection via CreateRemoteThread?

本文关键字：DLL 注入 CreateRemoteThread 通过      更新时间：2023-10-16

让我们假设远程线程过程如下所示：

DWORD __stdcall ThreadProc (void *pData) {
    ThreadData *p = (ThreadData*)pData; // Contains function references and strings
    p->MessageBoxW(NULL, p->Message, p->Title, MB_OK);
}

然后一切正常，p->MessageBoxW(...)按预期显示一个消息框。但我不想为我在远程线程中使用的每个函数调用GetProcAddress，所以我想我可以在我的模块中创建一个函数导出（EXE文件创建远程线程），这样远程线程只需调用LoadLibraryW将我的EXE文件作为模块加载到目标进程的地址空间，并调用GetProcAddress获取导出函数的地址来调用它。

typedef void (__stdcall *_Test) ();
extern "C" void __stdcall Test () {
    return;
}
DWORD __stdcall ThreadProc (void *pData) {
    ThreadData *p = (ThreadData*)pData; // Contains function references and strings
    HMODULE hLib = p->LoadLibraryW(p->LibPath);
    _Test pTest = (_Test)p->GetProcAddress(hLib, p->ProcName);
    pTest();
    p->FreeLibrary(hLib);
    return NULL;
}

这仍然很好用。但一旦我将导出的功能更改为

extern "C" void __stdcall Test () {
    MessageBoxW(NULL, L"Message", L"Title", MB_OK);
    return;
}

目标进程突然崩溃LoadLibrary不解析联运引用吗？是否可以将我的模块加载到目标进程的地址空间中，以便在不将所有函数地址传递给它的情况下对导出的函数进行编码

附加信息：对于所有复制代码的人，我必须禁用增量链接，构建为版本并添加模块定义文件以确保Test导出为Test而不是_Test@SoMeJuNk。由于某种原因，仅仅准备__declspec(dllexport)是不起作用的。模块定义文件看起来像这个

EXPORTS
    Test@0

ThreadData结构看起来像这个

typedef struct tagThreadData {
    typedef BOOL (__stdcall *_FreeLibrary) (HMODULE);
    typedef FARPROC (__stdcall *_GetProcAddress) (HMODULE, PSTR);
    typedef HMODULE (__stdcall *_LoadLibraryW) (LPWSTR);
    typedef DWORD (__stdcall *_MessageBoxW) (HWND, LPWSTR, LPWSTR, DWORD);
    _FreeLibrary FreeLibrary;
    _GetProcAddress GetProcAddress;
    _LoadLibraryW LoadLibraryW;
    _MessageBoxW MessageBoxW;
    WCHAR LibPath[100];
    WCHAR Message[30];
    CHAR ProcName[10];
    WCHAR Title[30];
} ThreadData, *PThreadData;

我想出了一个临时解决方案：将所有远程代码放入一个实际的DLL中。但把代码放入DLL并不是我的目标，所以如果有人想出一个聪明的解决方案，EXE文件是注入程序和被注入的模块，我会把新的答案标记为正确的。

尽管有很多关于如何将实际DLL注入另一个进程的地址空间的教程，但我仍然给出了我的解决方案。我只为UNICODE和64位编写了我的原始解决方案，但我尽了最大努力使其同时适用于ASCII和UNICODE以及32位和64位。但让我们开始吧。。。

首先，解释的基本步骤

  1. 获得至少具有以下访问权限的目标进程的句柄

    PROCESS_CREATE_THREAD
PROCESS_QUERY_INFORMATION
PROCESS_VM_OPERATION
PROCESS_VM_WRITE
PROCESS_VM_READ

  2. 为远程线程过程以及加载目标dll及其"入口点"所需的数据和函数指针分配内存（我不是指实际的入口点DllMain，而是一个设计为从远程线程内调用的函数）

    PVOID pThread = VirtualAllocEx(hProc, NULL, 4096, MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE);

  3. 将远程线程过程和重要数据复制到目标进程

    WriteProcessMemory(hProc, pThread, ThreadProc, ThreadProcLen, NULL);
WriteProcessMemory(hProc, pParam, &data, sizeof(ThreadData), NULL);

  4. 创建远程线程。该线程将把目标dll加载到目标进程的地址空间中，并调用其"入口点"

    HANDLE hThread = CreateRemoteThread(hProc, NULL, 0, (PTHREAD_START_ROUTINE)pThread, pParam, NULL, NULL);

  5. 可选：等待线程返回

    WaitForSingleObject(hThread, INFINITE);
DWORD threadExitCode;
GetExitCodeThread(hThread, &threadExitCode);

  6. 关闭线程句柄，释放内存，关闭进程句柄

    CloseHandle(hThread);
VirtualFreeEx(hProc, pThread, 4096, MEM_RELEASE);
CloseHandle(hProc);

这是我的ThreadProc和ThreadData结构。ThreadProc是由CreateRemoteThread调用的远程线程过程，LoadLibrary应该是目标dll，因此它可以调用目标dll的"入口点"。ThreadData结构包含LoadLibrary、GetProcAddress和FreeLibrary的地址、目标dll的路径TargetDll和"入口点"DllEntry的名称。

typedef struct {
    typedef BOOL (__stdcall *_FreeLibrary) (HMODULE);
    typedef FARPROC (__stdcall *_GetProcAddress) (HMODULE, LPCH);
    typedef HMODULE (__stdcall *_LoadLibrary) (LPTSTR);
    typedef void (__stdcall *_DllEntry) ();
    _LoadLibrary LoadLibrary;
    TCHAR TargetDll[MAX_PATH];
    _GetProcAddress GetProcAddress;
    CHAR DllEntry[50]; // Some entrypoint designed to be
                       // called from the remote thread
    _FreeLibrary FreeLibrary;
} ThreadData, *PThreadData;

// ThreadProcLen should be smaller than 3400, because ThreadData can
// take up to 644 bytes unless you change the length of TargetDll or
// DllEntry
#define ThreadProcLen       (ULONG_PTR)2048
#define SPY_ERROR_OK        (DWORD)0
#define SPY_ERROR_LOAD_LIB  (DWORD)1
#define SPY_ERROR_GET_PROC  (DWORD)2
DWORD ThreadProc (PVOID pParam) {
    DWORD err = SPY_ERROR_OK;
    PThreadData p = (PThreadData)pParam;
    // Load dll to be injected
    HMODULE hLib = p->LoadLibrary(p->TargetDll);
    if (hLib == NULL)
        return SPY_ERROR_LOAD_LIB;
    // Obtain "entrypoint" of dll (not DllMain)
    ThreadData::_DllEntry pDllEntry = (ThreadData::_DllEntry)p->GetProcAddress(hLib, p->DllEntry);
    if (pDllEntry != NULL)
        // Call dll's "entrypoint"
        pDllEntry();
    else
        err = SPY_ERROR_GET_PROC;
    // Free dll
    p->FreeLibrary(hLib);
    return err;
}

然后是将远程线程过程注入目标进程的地址空间的实际代码

int main(int argc, char* argv[]) {
    // DWORD pid = atoi(argv[1]);
    // Open process
    HANDLE hProc = OpenProcess(PROCESS_ALL_ACCESS, FALSE, pid);
    if (hProc != NULL) {
        // Allocate memory in the target process's address space
        PVOID pThread = VirtualAllocEx(hProc, NULL, 4096, MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE);
        if (pThread != NULL) {
            PVOID pParam = (PVOID)((ULONG_PTR)pThread + ThreadProcLen);
            // Initialize data to be passed to the remote thread
            ThreadData data;
            HMODULE hLib = LoadLibrary(TEXT("KERNEL32.DLL"));
            data.LoadLibrary = (ThreadData::_LoadLibrary)GetProcAddress(hLib, "LoadLibrary");
            data.GetProcAddress = (ThreadData::_GetProcAddress)GetProcAddress(hLib, "GetProcAddress");
            data.FreeLibrary = (ThreadData::_FreeLibrary)GetProcAddress(hLib, "FreeLibrary");
            FreeLibrary(hLib);
            _tcscpy_s(data.TargetDll, TEXT("..."));         // Insert path of target dll
            strcpy_s(data.DllEntry, "NameOfTheDllEntry");   // Insert name of dll's "entrypoint"
            // Write procedure and data into the target process's address space
            WriteProcessMemory(hProc, pThread, ThreadProc, ThreadProcLen, NULL);
            WriteProcessMemory(hProc, pParam, &data, sizeof(ThreadData), NULL);
            // Create remote thread (ThreadProc)
            HANDLE hThread = CreateRemoteThread(hProc, NULL, 0, (PTHREAD_START_ROUTINE)pThread, pParam, NULL, NULL);
            if (hThread != NULL) {
                // Wait until remote thread has finished
                if (WaitForSingleObject(hThread, INFINITE) == WAIT_OBJECT_0) {
                    DWORD threadExitCode;
                    // Evaluate exit code
                    if (GetExitCodeThread(hThread, &threadExitCode) != FALSE) {
                        // Evaluate exit code
                    } else {
                        // The thread's exit code couldn't be obtained
                    }
                } else {
                    // Thread didn't finish for some unknown reason
                }
                // Close thread handle
                CloseHandle(hThread);
            }
            // Deallocate memory
            VirtualFreeEx(hProc, pThread, 4096, MEM_RELEASE);
        } else {
            // Couldn't allocate memory in the target process's address space
        }
        // Close process handle
        CloseHandle(hProc);
    }
    return 0;
}

当LoadLibrary将目标dll加载到目标进程的地址空间时，被注入的dll有一个被调用的实际入口点DllMain，以及由远程线程过程调用的另一个"入口点"NameOfTheDllEntry（如果它可以位于第一位置）

// Module.def:
// LIBRARY NameOfDllWithoutExtension
// EXPORTS
//     NameOfTheDllEntry
__declspec(dllexport) void __stdcall NameOfTheDllEntry () {
    // Because the library is actually loaded in the target process's address
    // space, there's no need for obtaining pointers to every function.
    // I didn't try libraries other than kernel32.dll and user32.dll, but they
    // should be working as well as long as the dll itself references them
    // Do stuff
    return;
}

BOOL APIENTRY DllMain (HMODULE hLib, DWORD reason, PVOID) {
    if (reason == DLL_PROCESS_ATTACH)
        DisableThreadLibraryCalls(hLib);    // Optional
    return TRUE;
}
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