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rbmm/gist:0a9b675e675175b739a3b45bc9817e71

Created February 6, 2024 18:58
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  1. rbmm created this gist Feb 6, 2024.
    46 changes: 46 additions & 0 deletions gistfile1.txt
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,46 @@
    BOOL UnhookNT()
    {
    BOOL fOk = FALSE;

    if (HMODULE hmod = GetModuleHandleW(L"ntdll"))
    {
    if (PIMAGE_NT_HEADERS pinth = RtlImageNtHeader(hmod))
    {

    PVOID BaseAddress = (PBYTE)hmod + pinth->OptionalHeader.BaseOfCode;
    ULONG SizeOfCode = pinth->OptionalHeader.SizeOfCode;

    ULONG crc = RtlComputeCrc32(0, BaseAddress, SizeOfCode);

    if (PWSTR buf = new WCHAR[MINSHORT])
    {
    GetModuleFileNameW(0, buf, MINSHORT);
    if (NOERROR == GetLastError())
    {
    PROCESS_INFORMATION pi;
    STARTUPINFOW si = { sizeof(si) };
    if (CreateProcessW(buf, 0, 0, 0, 0, CREATE_SUSPENDED, 0, 0, &si, &pi))
    {
    NtClose(pi.hThread);
    ULONG op;
    if (VirtualProtect(BaseAddress, SizeOfCode, PAGE_EXECUTE_READWRITE, &op))
    {
    fOk = ReadProcessMemory(pi.hProcess, BaseAddress, BaseAddress, SizeOfCode, 0);
    VirtualProtect(BaseAddress, SizeOfCode, op, &op);
    }
    TerminateProcess(pi.hProcess, 0);
    NtClose(pi.hProcess);
    }
    }
    delete [] buf;
    }

    if (fOk)
    {
    DbgPrint("%08x vs %08x\n", crc, RtlComputeCrc32(0, BaseAddress, SizeOfCode));
    }
    }
    }

    return fOk;
    }