How to reverse engineering Flutter-based Android apps

cryptic

3 years ago

Tools to reverse flutter app

There are basically 3 tools to reverse Dart:

Darter [5]: this is a Python toolkit to parse libapp.so. It works for Flutter 2.5. Example of use here. Unfortunately, we have 2.13 which is significantly newer.
Doldrums [6]: this tool is meant to parse libapp.so and dump all classes of the isolate snapshots. Exactly what I am looking for, except it works for Flutter 2.10. There’s a fork currently focusing on 2.13. It isn’t finished yet. I tried to fix errors for my sample, by quickly moving out of issues it encountered, but I got no interesting decompiled output in the end (meaning my “quick fix” is too quick, and there’s more to be done to get it to work).
reFlutter [7]: this framework operates differently. The idea is to patch the sample and use a patched version of the Flutter library. Then, to write Frida hooks and dynamically analyze calls to the patched library.