His research interests include malware analysis, vulnerability assessment, the underground economy, the security of social networks, voting security and misinformation detection, and the applications of machine learning and artificial intelligence to security problems.

He has been the Program Chair of the International Symposium on Recent Advances in Intrusion Detection (RAID 2003), of the ISOC Symposium on Network and Distributed Systems Security (NDSS 2009), of the IEEE Symposium on Security and Privacy (Oakland 2010-2011), and of the ACM Conference on Computer and Communications Security (CCS 2020-2021).

He is known for organizing and running, since 2003, a yearly educational Capture The Flag hacking contest, called iCTF, that every year involves dozens of teams around the world.