Detection of Brute-Force Attacks in End-to-End Encrypted Network Traffic

Network intrusion detection systems (NIDSs) can detect attacks in network traffic. However, the increasing ratio of encrypted connections on the Internet restricts their ability to observe such attacks. This paper proposes a completely passive method that allows to detect brute-force attacks in encrypted traffic without the need to decrypt it. For that, we propose five novel metrics for attack detection which quantify metadata like packet size or packet timing.