~/talk

Endoscope: Unpacking Android Apps with VM-Based Obfuscation

Talkat Black Hat USA 2023 · 2023-08-05..08-10· [android, security]
name:Fan Wu
links:none on file
links:none on file
slides:none on file

Shows a practical method that recovers original Dalvik bytecode from VM‑obfuscated Android apps by combining hooking of native registration (keeps hook registerNative), instruction‑level instrumentation with QBD to trace dispatcher/handler execution, and per‑handler genetic signature hashes that tolerate pointer and immediate differences. Demonstrates restoring Rhino bytecode to AST via Rhino’s Source API for one case and a general pipeline that learns handler→bytecode mappings from a seeded app and then successfully unmasks handlers in the wild, though it requires accessible entry functions and typical packer translation patterns.

AI-written summary · about

  1. 0:00VM-based obfuscation on Android
  2. 3:03Rhino bytecode in malware
  3. 8:06Reversing Rhino bytecode
  4. 11:48Challenges in unpacking VM obfuscation
  5. 16:58Mapping relations via execution traces
  6. 26:27Insights on VM obfuscation trends
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