Transformer-based Model for Multi-tab Website Fingerprinting Attack

While the anonymous communication system Tor can protect user privacy, website fingerprinting (WF) attackers can still identify the websites that users access over encrypted network connections by analyzing the metadata generated during network communication. Despite the emergence of new WF attack techniques in recent years, most research in this area has focused on pure traffic traces generated from single-tab browsing behavior. However, multi-tab browsing behavior significantly degrades the performance of WF classification models based on the single-tab assumption. As a result, some research has shifted its focus to multi-tab WF attacks, although most of these works have limited utilization of the mixed information contained in multi-tab traces. In this paper, we propose an end-to-end multi-tab WF attack model, called Transformer-based model for Multi-tab Website Fingerprinting attack (TMWF). Inspired by object detection algorithms in computer vision, we treat multi-tab WF recognition as a problem of predicting ordered sets with a maximum length. By adding enough single-tab queries to the detection model and letting each query extract WF features from different positions in the multi-tab traces, our model's Transformer architecture capitalizes more fully on trace features. Paired with our new proposed model training approach, we accomplish adaptive recognition of multi-tab traces with varying numbers of web pages. This approach successfully eliminates a strong and unrealistic assumption in the field of multi-tab WF attacks - that the number of tabs contained in a sample belongs to the attacker's prior knowledge. Experimental results in various scenarios demonstrate that the performance of TMWF is significantly better than existing multi-tab WF attack models. To evaluate model performance in more authentic scenarios, we present a dataset of multi-tab trace data collected from real open-world environments.