Dom-BERT: Detecting Malicious Domains with Pre-training Model

Domain Name System (DNS) is widely abused by attackers, which thus makes malicious domain detection a crucial routine task for operators to combat cyber crimes. Existing classification-based models often struggle to achieve high accuracy in practical settings due to the class imbalance of the task. Moreover, inference-based models, which hinge upon the resolution similarity between domains, often fail to harness the full potential of linguistic associations among domains. This paper first conducts a detailed analysis of the characteristics of malicious domains and contrasts them with those of benign ones, using a real-life passive DNS dataset obtained from several major ISPs (Internet Service Providers). With this basis, we then propose an efficient solution for the detection of malicious domains, called Dom-BERT. To adeptly capture the resolution associations among domains, Dom-BERT constructs a heterogeneous graph and incorporates a pruning module, facilitating the modeling of relationships among domains, clients, and hosting servers. Building upon this graph, we employ techniques such as random walks with restart and a domain association prediction downstream task to compute similarity scores for domains. These scores are then used to fine-tune the pre-trained BERT model. The performance of Dom-BERT is evaluated using our passive DNS logs. The results notably illustrate that Dom-BERT surpasses the state-of-the-art solutions, achieving higher F1 scores and demonstrating resilience to class imbalance. (The implementation of Dom-BERT is publicly available at https://github.com/yutian99/Dom-BERT ).