The Trouble with Tor

This post details Cloudflare's approach to handling traffic from the Tor network, which presents a unique challenge due to the high percentage of malicious requests originating from Tor exit nodes and the inherent anonymity that prevents traditional reputation-based filtering. The post discusses the trade-offs between security, anonymity, and convenience, and the implementation of CAPTCHAs (specifically Google's reCAPTCHA) as a primary mechanism to distinguish automated malicious traffic from legitimate human users. It also introduces open-sourced tools like 'torhoney' and 'torexit' for analyzing Tor exit node reputation and longevity, and discusses potential future improvements such as treating GET requests differently and allowing customers to configure rules for Tor traffic.