CVE-2024-0450

CPython zipfile module vulnerable to quoted-overlap zip-bombs.

• CVSS 6.2
• CWE-405
• Input Validation and Sanitization
• Remote

An issue was found in the CPython `zipfile` module affecting versions 3.12.1, 3.11.7, 3.10.13, 3.9.18, and 3.8.18 and prior. The zipfile module is vulnerable to “quoted-overlap” zip-bombs which exploit the zip format to create a zip-bomb with a high compression ratio. The fixed versions of CPython makes the zipfile module reject zip archives which overlap entries in the archive.

CVE

CVE-2024-0450

CWE

CWE-405

CVSS base score

6.2

Published

2024-03-19

OWASP

A06 Security Misconfiguration

Orthogonal defect classification

Function

Code defect classification

Incorrect Functionality

Category

Input Validation and Sanitization

Subcategory

Insecure Parsing or Deserialization

Accessibility scope

Remote

Impact

Denial of Service (DoS)

Affected component

Python `zipf

Fixed by upgrading

Yes

Solution

Upgrade to CPython version 3.12.2 or later.

import zipfile
import io

with zipfile.ZipFile('example.zip', 'w') as zf:
    zf.writestr('file1.txt', b'A' * (10**6)) 
    zf.writestr('file2.txt', b'B' * (10**6)) 

with zipfile.ZipFile('example.zip', 'r') as zf:
    print(zf.namelist())
    zf.extractall('extracted_files')

import zipfile
import os

with zipfile.ZipFile('example.zip', 'w') as zf:
    zf.writestr('file1.txt', b'A' * (10**6)) 
    zf.writestr('file2.txt', b'B' * (10**6)) 

def extract(zip_file, extract_to):
    with zipfile.ZipFile(zip_file, 'r') as zf:
        for file_name in zf.namelist():
            if os.path.commonprefix([os.path.abspath(file_name), os.path.abspath(extract_to)]) != os.path.abspath(extract_to):
                print(f"Suspicious file detected: {file_name}")
                return
        zf.extractall(extract_to)

extract('example.zip', 'extracted_files')

import zipfile

# Create a zip bomb payload with overlapping entries
with zipfile.ZipFile('exploit.zip', 'w') as zf:
    zf.writestr('file1.txt', b'A' * (10**6))  # 1 MB file
    zf.writestr('file2.txt', b'B' * (10**6))  # 1 MB file
    # Overlapping entry to exploit the vulnerability
    zf.writestr('file1.txt', b'A' * (10**6))  # Overlapping entry

@misc{vaitp:cve20240450,
  title        = {{CPython zipfile module vulnerable to quoted-overlap zip-bombs.}},
  author       = {Bogaerts, Fr\'ed\'eric and Ivaki, Naghmeh and Fonseca, Jos\'e},
  year         = {2024},
  note         = {VAITP Python Vulnerability Dataset, entry CVE-2024-0450},
  howpublished = {\url{https://netpack.pt/vaitp/vulnerability/CVE-2024-0450/}}
}