I found this security bug in one of the prominent food startups of India. All their customer data including residential info , order info and contact details were vulnerable. Exposed Customer Data Look at the following code. .route(“/customer/info”)def customer_info():customer_id = requests.args.get(‘customer_id’)customer = customers.query.filter(Customer.id==customer_id).one()customer_schema.jsonify(customer) @app A customer of id 5453 will have the following request URL http://server_ip/customer/info?customer_id=5453 Now look at the URL, the id is a number. A hacker will try changing the number from 5453 to 5454 http://server_ip/customer/info?customer_id=5454 This will allow him to fetch details of the customer with id 5454, which he is not supposed to see. Now he can write a script which loops through customer ids and fetch information; he has hacked into a company’s confidential data. This can be prevented by adding authentication to check if the user has privileges to access the data. A unique string identifier is much better than an integer identifier. If you are interested in making cloud apps. Do checkout my book :) . Get the free chapters . Cloud Is a Piece of Cake here