Discovering Concrete Attacks on Website Authorization by Formal Analysis, C. Bansal, K. Bhargavan & S. Maffeis. CSF 2012

Social sign-on and social sharing are becoming an ever more popular feature of web applications. This success is largely due to the APIs and support offered by prominent social networks, such as Facebook, Twitter, and Google, on the basis of new open standards such as the OAuth 2.0 authorization protocol. A formal analysis of these protocols must account for malicious websites and common web application vulnerabilities, such as cross-site request forgery and open redirectors. We model several configurations of the OAuth 2.0 protocol in the applied pi-calculus and verify them using ProVerif. Our models rely on WebSpi, a new library for modeling web applications and web-based attackers that is designed to help discover concrete website attacks. Our approach is validated by finding dozens of previously unknown vulnerabilities in popular websites such as Yahoo and WordPress, when they connect to social networks such as Twitter and Facebook.

Detailed Vulnerability Reports


Running the Scripts

You will need to have the latest version of ProVerif in order to be able to test the library and the models. ProVerif can be downloaded from here.
Then, you can use the following command to analyze the models:

proverif -lib https apps.pv