Net-track: Generic Web Tracking Detection Using Packet Metadata

While third-party trackers breach users' privacy by compiling large amounts of personal data through web tracking techniques, combating these trackers is still left at the hand of each user. Although network operators may attempt a network-wide detection of trackers through inspecting all web traffic inside the network, their methods are not only privacy-intrusive but of limited accuracy as these are susceptible to domain changes or ineffective against encrypted traffic. To this end, in this paper, we propose Net-track, a novel approach to managing a secure web environment through platform-independent, encryption-agnostic detection of trackers. Utilizing only side-channel data from network traffic that are still available when encrypted, Net-track accurately detects trackers network-wide, irrespective of user's browsers or devices without looking into packet payloads or resources fetched from the web server. This prevents user data from leaking to tracking servers in a privacy-preserving manner. By measuring statistics from traffic traces and their similarities, we show distinctions between benign traffic and tracker traffic in their traffic patterns and build Net-track based on the features that fully capture trackers' distinctive characteristics. Evaluation results show that Net-track is able to detect trackers with 94.02% accuracy and can even discover new trackers yet unrecognized by existing filter lists. Furthermore, Net-track shows its potential for real-time detection, maintaining its performance when using only a portion of each traffic trace.