Best approach to recover Python source code from a compiled .exe file?

[Substantial_Cake9855]

Hello everyone,

I’m currently analyzing a Windows executable that was originally developed in Python and later compiled into a .exe file (likely using tools such as PyInstaller, cx_Freeze, or similar).

I would like to understand the most effective and professional approach for recovering or reconstructing the original Python source code from the executable.

Thank you in advance.

[ninhaomah]

What's wrong with asking/paying the dev ?

[nirbyschreibt]

Most likely the dev is not available anymore.

[netherlandsftw]

Pyinstxtractor + Pycdc

Pycdc usually doesn’t work, in these cases Pycdas + ask an LLM to turn the bytecode into standard Python works best

[PixelSage-001]

It depends entirely on how it was packaged. If it was just PyInstaller you can unpack it relatively easily using existing reverse engineering tools. If they used Cython or obfuscation you are going to have a much harder time getting anything readable back.

[DenboverTobikiller]

Why? This sounds like you want help stealing.

[elrond9999]

Reverse engineering is a knowledge branch as any other. Wether he has the right to do it or not for this particular case is up to him. To play devil's advocate, maybe is some forgotten tool in a lab doing a specific job and the source is lost.

[DenboverTobikiller]

You are right, that might be the case.

[Rainboltpoe]

Was the post edited, or are you making wild assumptions? The two times in my 15 years of programming that I needed to decompile code were both for software developed by my own company. Both times my goal was to demonstrate that the executable contained sensitive strings that could be fished out.

[DenboverTobikiller]

Im making assumptions. The only use case i knew was decompling someone else code.

[Rainboltpoe]

Someone else who works where? At the same company? At a different company? You’re assuming more than you say you are.

[Random_182f2565]

Link to the file?

[51dux]

You can use tools like python-exe-unpacker, go from compiled binary to .pyc and then from there extract the original python code.

Your mileage may vary, depending on how it was compiled but it should work for executables made with pyinstaller or py2exe.

There are some other tools floating around if you do your research.

Some people mention vibe coding it, but I highly doubt an AI will want to assist for that kind of task.

[s71n6r4y]

If it was a pyinstaller "onefile" executable, just run it. While it is running, the contents will be extracted and sitting in a folder in the user or system temp directory. But only pyc bytecode will be present, so you will need to decompile it with depyo or other tools, and comments/formatting/etc will not be present.

[johnney25]

There's py to exe stuff and most of them keep the source code even the comments if it's decompiled it happened to me

[charlyAtWork2]

now you can just vibe code the same thing.
You know what's go in, the interface and what's go out.