Basic DLL Injector

injector.cpp

1#include <Windows.h>
2#include <stdio.h>
3
4int main() {
5    char cmdLine[] = "SPEED2.EXE /s";
6    char dllPath[] = "nfsu2.dll";
7
8    STARTUPINFOA si{};
9    PROCESS_INFORMATION pi{};
10    si.cb = sizeof(si);
11
12    if (!CreateProcessA(
13        nullptr,
14        cmdLine,
15        nullptr, nullptr,
16        FALSE,
17        CREATE_SUSPENDED,
18        nullptr, nullptr,
19        &si, &pi))
20    {
21        printf("CreateProcess failed: %lu\n", GetLastError());
22        return 0;
23    }
24
25    SIZE_T len = strlen(dllPath) + 1;
26
27    void* remoteBuf = VirtualAllocEx(
28        pi.hProcess,
29        nullptr,
30        len,
31        MEM_COMMIT | MEM_RESERVE,
32        PAGE_READWRITE);
33
34    WriteProcessMemory(
35        pi.hProcess,
36        remoteBuf,
37        dllPath,
38        len,
39        nullptr);
40
41    HMODULE k32 = GetModuleHandleA("kernel32.dll");
42    auto pLoadLibraryA =
43        (LPTHREAD_START_ROUTINE)GetProcAddress(k32, "LoadLibraryA");
44
45    HANDLE hThread = CreateRemoteThread(
46        pi.hProcess,
47        nullptr,
48        0,
49        pLoadLibraryA,
50        remoteBuf,
51        0,
52        nullptr);
53
54    WaitForSingleObject(hThread, INFINITE);
55
56    CloseHandle(hThread);
57    VirtualFreeEx(pi.hProcess, remoteBuf, 0, MEM_RELEASE);
58
59    ResumeThread(pi.hThread);
60
61    CloseHandle(pi.hThread);
62    CloseHandle(pi.hProcess);
63
64    return 1;
65}
66