Detecting and Defending CSRF at API-Level

Cross-Site Request Forgery (CSRF) vulnerabilities are severe web vulnerabilities since their characteristics of extreme concealment and heavy harmfulness. However, they have received marginal attention from both the academic and the industry and the detection and protection of CSRF vulnerabilities are still performed predominantly manually. This paper proposes CSRFSolver for API-level CSRF detection and protection with two components: CSRF detector and CSRF defender. The former helps to identify and locate CSRF points where they need CSRF protection, and the latter provides CSRF protection by generating and verifying CSRFToken. We evaluate the effectiveness and efficiency of CSRFSolver on Cisco Webex public URL APIs with the state-of-the-art method. The results indicate that CSRFSolver can effectively and efficiently protect the system from CSRF attacks and have no side effects on systems' functionality. Meanwhile, the practical usefulness of CSRFSolver has also been verified through four years of deployment in Cisco Webex.