Isra Elsharef, Zhen Zeng (University of Wisconsin-Milwaukee), Zhongshu Gu (IBM Research)

In recent years, security engineers in product teams have faced new challenges in threat modeling due to the increasing complexity of product design and the evolving nature of threats. First, security engineers must possess a thorough understanding of how to translate the abstract categories of threat modeling methodology into specific security threats relevant to a particular aspect of product design. Without such indepth knowledge, applying threat modeling in practice becomes a difficult task. Second, security engineers must be aware of current vulnerabilities and be able to quickly recall those that may be relevant to the product design. Therefore, for effective threat modeling, a deep understanding of a product’s design and the background knowledge to connect real-time security events with specific design principles embedded in large volumes of technical specifications is required. This can result in a lot of human effort invested in parsing, searching, and understanding what is being built through design documents and what threats are relevant based on that information. We observe that the recent emergence of large language models (LLMs) may significantly change the landscape of threat modeling by automating and accelerating the process with their language understanding and logical reasoning capabilities. In this paper, we have developed a novel LLM-based threat modeling system by leveraging NLP techniques and an open-source LLM to decrease the required human effort above in the threat modeling process. In the evaluation, two major questions of threat modeling (MQ1 and MQ2) are considered in the proposed workflow of Task 1 and Task 2, where the NLP techniques assist in parsing and understanding design documents and threats, and the LLM analyzes and synthesizes volumes of documentation to generate responses to related threat modeling questions. Our initial findings reveal that over 75% of the responses meet the expectations of human evaluation. The Retrieval Augmented Generation (RAG)-enhanced LLM outperforms the base LLM in both tasks by responding more concisely and containing more meaningful information. This study explores a novel approach to threat modeling and demonstrates the practical applicability of LLM-assisted threat modeling.