Sanitize user input

Always sanitize and validate user-controlled input before using it in sensitive operations, and never hard-code credentials in source code.

For command execution:

• User input should never be directly interpolated into shell commands
• Use parameter substitution libraries or sanitize inputs with allowlists
• Prefer higher-level APIs when available instead of raw shell commands

For credential management:

• Store credentials in environment variables or dedicated secret management systems
• Load credentials at runtime, not in source code
• Use different credentials for development and production environments

Bad example (command injection vulnerability):

username = request.get_json().get('username')
os.system(f'docker compose -f {compose_file} -p n8n-{username} up -d')

Better example:

import shlex
import subprocess

username = request.get_json().get('username')
# Validate username format with a strict pattern
if not re.match(r'^[a-zA-Z0-9_-]+$', username):
    return jsonify({'error': 'Invalid username format'}), 400

# Use subprocess with parameters list instead of shell=True
subprocess.run(['docker', 'compose', '-f', compose_file, '-p', f'n8n-{username}', 'up', '-d'])

Bad example (credential management):

uri = "mongodb+srv://akaneai420:ilovehentai321@cluster0.jwyab3g.mongodb.net/?retryWrites=true"

Better example:

# Load from environment variables
db_user = os.getenv('DB_USER')
db_password = os.getenv('DB_PASSWORD')
db_host = os.getenv('DB_HOST')
uri = f"mongodb+srv://{db_user}:{db_password}@{db_host}/?retryWrites=true"

These practices help prevent both command injection attacks and credential leakage, which are common security vulnerabilities in web applications.