| Feature | Description | |---------|-------------| | | A dispatch loop reads VM bytecode (opcodes + operands) from a virtualized code section. | | Handler Functions | Each VM instruction is implemented as a native (x86/x64) function that emulates one operation (e.g., ADD , JCC , PUSH ). | | Bytecode | Custom, non-Intel instruction set. No public mapping; varies per build. | | Mutations | The same VM bytecode can map to different handler sequences across builds. | | Anti-debugging | int 3 , rdtsc checks, NtQueryInformationProcess , IsDebuggerPresent , CheckRemoteDebuggerPresent , and TLS callbacks. | | Anti-dumping | Encrypted sections, imports erased, dynamic API resolution via hash. |
: Research by Jonathan Salwan on GitHub demonstrates using symbolic execution and LLVM to automatically deobfuscate virtualized functions. vmprotect reverse engineering
Alex needed that key to infiltrate the network. He looked at the emulation output. The derivation algorithm was a custom elliptic curve signing routine, heavily obfuscated. | Feature | Description | |---------|-------------| | |
VMProtect reverse engineering is not a single technique but a war of attrition. It pits the deterministic logic of the computer against the patience of the human. The protector forces the analyst to stop thinking in x86 and start thinking in abstract state machines. No public mapping; varies per build
To frustrate the above process, VMProtect adds: