Python Zipfile compression method is not supported

Question

The times when this worked were when I used ZIPCrypto compression. It's with AES-256 that it fails. How to get around this please?

I previously had success using the following Python code to open a password protected .zip file created with 7-Zip:

import zipfile

zip_file = zipfile.ZipFile('crack_me.zip')
output_verbose = 1  # increase that for long password list
with open('passwords.txt', 'rb') as password_list:
    for index, line in enumerate(password_list):
        try:
            pwd = line.strip(b'\r\n')
            zip_file.extractall(pwd=pwd)
        except RuntimeError as e:
            print(e)
            if index % output_verbose == 0:
                print('{}. The {} word not matched.'.format(index + 1, pwd))
        else:
            print('{}. Wow ! found the password: {}'.format(index + 1, pwd))
            break

zip_file.close()

However, for no understandable reason, it has only worked a couple of times out of many attempts. Most times is gives "That compression method is not supported" for the exception.

I've tried deleting, renaming, re-creating the .zip file but no success. It makes no sense to me that it works occasionally.

I tried to simplify the issue as below:

import zipfile

zip_file = zipfile.ZipFile('crack_me.zip')
try:
    zip_file.extractall(pwd=b"password")
    print('Opened')
except RuntimeError as e:
    print(e)

But I get the same exception. I've tried variations of pwd such as bytes("password", "utf-8) and others.

The provided password opens the .zip file when opening with 7-Zip.

What is going on here please?

Related https://stackoverflow.com/questions/32797851/how-to-read-contents-of-7z-file-using-python — snakecharmerb, Jul 05 '20 at 09:30
Can you please supply the exact command line arguments you may have passed to `7z` which you created the zip file with? If you did not explicitly specified the standard zip method (i.e. passing the `-tzip` flag), Python's `zipfile` module will be unable to open it. — metatoaster, Jul 05 '20 at 09:31
Also relevant https://stackoverflow.com/questions/31743127/python3-lzma-unpack-7z-file — snakecharmerb, Jul 05 '20 at 09:32
Edited: It's with AES-256 that it fails. How to get around this please? — Robin Andrews, Jul 05 '20 at 09:32

score 6 · Answer 1 · edited Nov 24 '21 at 06:25

6

Try using pyzipper. Here is a sample script:

import pyzipper


password = 'abc'

with pyzipper.AESZipFile('yourdocument.zip', 'r', compression=pyzipper.ZIP_DEFLATED, encryption=pyzipper.WZ_AES) as extracted_zip:
    extracted_zip.extractall(pwd=str.encode(password))

edited Nov 24 '21 at 06:25

Mike

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answered Nov 23 '21 at 18:07

Thomas Vélez

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score 4 · Answer 2 · edited Sep 05 '21 at 13:11

4

In order for the zipfile library to work on a password protected zip you need to have ticked the "Zip legacy encryption" option when setting up the password.

edited Sep 05 '21 at 13:11

Freddy Mcloughlan

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answered Dec 09 '20 at 00:09

Dominte Florin-Iulian

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Python Zipfile compression method is not supported

2 Answers2