I found a security hole on Amazon last August. While looking at their HTTP headers, I happened to notice that the entire amazon.com domain was susceptible to clickjacking attacks. If I could trick you into clicking anywhere on a webpage I controlled, I could get you to buy any product that’s available for sale on Amazon. By the way, that includes any fake products that I added to Amazon myself. For the hack to work, you needed to be signed into your Amazon account and have one-click purchasing turned on. I created a working proof-of-concept that looked like this:
Clicking either button caused an instant purchase of the movie Click (get it?). I resisted the temptation to use the exploit to send myself a million dollars worth of free Amazon gift cards, and instead responsibly disclosed it to the Amazon security team. It took them months to fix it, but the security hole has finally been closed using the x-frame-options header that I recommended.
This hack is classic clickjacking. I created a transparent iframe containing a product page on amazon.com that had been carefully positioned so when you think you’re clicking on my page, you’re actually clicking the “Buy now” button on their site instead. Here’s the code for the no longer working proof of concept.