Themida replaces standard API calls (like CreateFile ) with calls to internal Thunk code.
. This engine creates a "Virtual Machine" (VM) with its own custom instruction set. The Challenge
// Get the base address of the mapped file LPCVOID lpBaseAddress = MapViewOfFile(hMapFile, FILE_MAP_READ, 0, 0, 0); if (lpBaseAddress == NULL) printf("Failed to map view of file\n"); CloseHandle(hMapFile); CloseHandle(hFile); return 1;
: To unpack it, a researcher must "de-virtualize" the instructions, mapping the fake commands back to real x86/x64 assembly code. 2. The Anti-Debugger Minefield