Explore a comprehensive analysis of active routing attacks on the Tor network and learn about innovative countermeasures in this IEEE Symposium presentation. Delve into a new measurement study on Tor's resilience to BGP prefix attacks, and discover how high-bandwidth ASes can be more vulnerable. Examine a novel guard relay selection algorithm that improves client security by up to 166%. Investigate a live BGP monitoring system capable of detecting routing anomalies in real-time, including simulated and real-world hijack attacks. Gain insights into anonymity, correlation analysis, and performance evaluation of proposed solutions to safeguard Tor against network-level adversaries.