decompile-a-hermes-react-native-binary.md

Decompile a Hermes React Native Binary

1. Pull APK from device

adb shell pm list packages | grep <app_name>
adb shell pm path <package_name>
adb pull /data/app/<package_name>-<random>/base.apk .

1. Decompile APK resources

   apktool d base.apk -o output_folder

2. Locate React Native bundle

   cd output_folder/assets/
   ls

3. Check if Hermes bytecode

   file index.android.bundle

4. Get Hermes decompiler

   git clone https://github.com/cognisys/hermes-dec.git
   cd hermes-dec
   pip3 install -r requirements.txt

5. Disassemble Hermes bytecode

   python3 hbc_disassembler.py ../index.android.bundle disasm_out

6. Decompile to JavaScript

   python3 hbc_decompiler.py ../index.android.bundle decompiled_out

7. (Optional) Beautify/Deobfuscate JS

   npx prettier --write decompiled_out/*.js