Does anybody have a suggestion for (non commercial) software to decompile "byte-code" Python (.pyc) files?
Everything I've found seems to break...
asked Apr 10, 2013 at 14:02
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3tried uncompyle2 ?– AngeApr 10, 2013 at 14:10
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2I haven't read it yet so I won't offer as an answer but A Problem Course in Compilation: From Python to x86 Assembly might be of use. link– alexanderhApr 10, 2013 at 15:18
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Alex, you kill me. Another PDF to my huge "To read" stack. Looks pretty interesting, thanks ;)– Carlos GarciaApr 10, 2013 at 17:16
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possible duplicate of What are the tools to analyze Python bytecode?– jvoisinNov 7, 2013 at 18:08
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uncompyle6 has now superseded uncomplye2. credit to other answer for helping me learn this: stackoverflow.com/a/14808336/10278– pestophagousAug 30, 2018 at 17:50
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7 Answers
What Python version you're decompiling? Py3k is not well supported, but there are quite a few decompilers for 2.x. One of the latest projects is this:
https://github.com/Mysterie/uncompyle2
It runs on Python 2.7 but supports decompiling 2.5 to 2.7.
Note that some commercial projects has been known to use modified Python interpreters. Modifications can include:
- bytecode files encryption
- changed opcode values or additional opcodes
- a heavily customized runtime (e.g. Stackless Python)
If you need to handle this, one approach is to convert non-standard bytecode to standard one and then use the usual decompilers (this apparently was used by the people from above project to decompile Dropbox code). Another is to change the decompiler to directly support the variations.
answered Apr 10, 2013 at 14:12
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4update from 2018 (five years later): uncompyle6 has now superseded uncomplye2. credit to other answer for helping me learn this: stackoverflow.com/a/14808336/10278 Aug 30, 2018 at 17:50
You might find pyREtic from Immunity to be useful. The presentation from BlackHat USA 2010 on pyREtic is here (YouTube).
pyREtic
Reverse Engineer Obfuscated Python Bytecode This toolkit allows you to take a object in memory back to source code, without needing access to the bytecode directly on disk. This can be useful if the applictions pyc's on disk are obfuscated in one of many ways.
I, of course, use uncompyle6. Disclaimer: I work on this project.
I've written at length about the uncompyle6 and pycdc here.
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1I did use this for a CTF, I am impressed by the quality of the code generated (for a simple pyc in my case). Nov 23, 2022 at 10:24
For initial and rough Python bytecode disassembly, I would be using the Python standard library dis module: https://docs.python.org/2/library/dis.html
Here is what you're looking for, I just came across a fully working Python decompiler named "Easy Python Decompiler".
There is also an open-source Python (.pyc) decompiler, called Decompyle++
Decompyle++ aims to translate compiled Python byte-code back into valid and human-readable Python source code. While other projects have achieved this with varied success, Decompyle++ is unique in that it seeks to support byte-code from any version of Python.
I recommend uncompyle6. it can decompile pyc/pyo files and it is compatible with python 3
pip install uncompyle6uncompyle6 FILE.pyc
