CreateRemoteThread returning ERROR_ACCESS_DENIED - Windows 7 DLL Injection

Question

I'm trying to write a program that uses CreateRemoteThread to inject a dll.

The problem is that CreateRemoteThread is refusing to work. GetLastError() is returning 5 which is ERROR_ACCESS_DENIED. I cant figure why!

I am working from this video http://www.youtube.com/watch?v=H3O3hmXkt1I .

#include <iostream>
#include <direct.h>
#include <Windows.h>
#include <TlHelp32.h>

using namespace std;


char* GetCurrentDir()
{
    char*   szRet = (char*)malloc(MAX_PATH);
    _getcwd(szRet, MAX_PATH);
    return szRet;
}

LPCTSTR SzToLPCTSTR(char* szString)
{
    LPTSTR  lpszRet;
    size_t  size = strlen(szString)+1;

    lpszRet = (LPTSTR)malloc(MAX_PATH);
    mbstowcs_s(NULL, lpszRet, size, szString, _TRUNCATE);

    return lpszRet;
}

void WaitForProcessToAppear(LPCTSTR lpcszProc, DWORD dwDelay)
{
    HANDLE          hSnap;
    PROCESSENTRY32  peProc;
    BOOL            bAppeared = FALSE;

    while(!bAppeared)
    {
        if((hSnap = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0)) != INVALID_HANDLE_VALUE)
        {
            peProc.dwSize = sizeof(PROCESSENTRY32);
            if(Process32First(hSnap, &peProc))
                while(Process32Next(hSnap, &peProc) && !bAppeared)
                    if(!lstrcmp(lpcszProc, peProc.szExeFile))
                        bAppeared = TRUE;
        }
        CloseHandle(hSnap);
        Sleep(dwDelay);
    }
}

DWORD GetProcessIdByName(LPCTSTR lpcszProc)
{
    HANDLE          hSnap;
    PROCESSENTRY32  peProc;
    DWORD           dwRet = -1;

    if((hSnap = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0)) != INVALID_HANDLE_VALUE)
    {
        peProc.dwSize = sizeof(PROCESSENTRY32);
        if(Process32First(hSnap, &peProc))
            while(Process32Next(hSnap, &peProc))
                if(!lstrcmp(lpcszProc, peProc.szExeFile))
                    dwRet = peProc.th32ProcessID;
    }
    CloseHandle(hSnap);

    return dwRet;
}

BOOL InjectDll(DWORD dwPid, char* szDllPath)
{
    DWORD   dwMemSize;
    HANDLE  hProc;
    LPVOID  lpRemoteMem, lpLoadLibrary;
    BOOL    bRet = FALSE;

    if((hProc = OpenProcess(PROCESS_ALL_ACCESS, FALSE, dwPid)) != NULL)
    {
        dwMemSize = strlen(szDllPath);
        if((lpRemoteMem = VirtualAllocEx(hProc, NULL, dwMemSize, MEM_COMMIT, PAGE_READWRITE)) != NULL)
            if(WriteProcessMemory(hProc, lpRemoteMem, szDllPath, dwMemSize, NULL))
            {
                lpLoadLibrary = GetProcAddress(GetModuleHandleA("kernel32.dll"), "LoadLibraryA");
                if(CreateRemoteThread(hProc, NULL, 0, (LPTHREAD_START_ROUTINE)lpLoadLibrary, lpRemoteMem, 0, NULL) != NULL)
                {
                    bRet = TRUE;
                }
                cout << GetLastError();
            }
    }
    CloseHandle(hProc);

    return bRet;
}

int main()
{
    char    szProc[MAX_PATH], szDll[MAX_PATH];
    char*   szDllPath = (char*)malloc(MAX_PATH);
    LPTSTR  lpszProc = NULL;

    for(;;)
    {
        cout << "Process: ";
        cin >> szProc;
        cout << "DLL: ";
        cin >> szDll;

        szDllPath = GetCurrentDir();
        strcat_s(szDllPath, MAX_PATH, "\\");
        strcat_s(szDllPath, MAX_PATH, szDll);

        cout << "Waiting for process.. ." << szDllPath << " " << szDll << endl;
        WaitForProcessToAppear(SzToLPCTSTR(szProc), 100);
        if(InjectDll(GetProcessIdByName(SzToLPCTSTR(szProc)), szDllPath))
            cout << "Injection Succeeded!" << endl;
        else
            cout << "Injection Failed!" << endl;
        cout << "\n";

    }

    return 0;

After a fair amount of googling I cant find a reason why this should not be working.

Does CreateRemoteThread not work under Windows 7 ? If it does, have I made any obvious mistakes ?

Answer 1

The reason it fails is because your code is 32-bit and your target process is 64-bit.

It doesn't matter how many privileges you own. Windows won't let that happen.

I had the same problem. Either you spawn a system 32-bit exe and inject that or port your code to 64-bit (which means it won't work on 32-bit systems).

EDIT

A long time ago, I found a nice way of injecting code into and from any processor mode-target. It involves dynamically switching the processor mode to that of (any)the target. Dubbed "heaven's gate". To do this you have to use inline assembly. So basically you can have both 64-bit and 32-bit code in a 32-bit exe, detect if the machine is 64-bit, then jump into 64-bit mode and run the 64-bit code. You'd then walk the imports to find ntdll and load 64-bit kernel.dll and other libraries. Here's a link to examples for any one who would be interested: http://bit.ly/19P0Lh3