Novel Actionable Counterfactual Explanations for Intrusion Detection Using Diffusion Models

Modern network intrusion detection systems (NIDSs) rely on complex deep learning models. However, the “black-box” nature of deep learning methods hinders transparency and trust in predictions, preventing the timely implementation of countermeasures against intrusion attacks. Although explainable AI (XAI) methods provide a solution to this problem by providing insights into the reasons behind the predictions, the explanations provided by the majority of them cannot be trivially converted into actionable countermeasures. In this work, we propose a novel tabular diffusion-based counterfactual explanation framework that can provide actionable explanations for network intrusion attacks. We evaluated our proposed algorithm against several other publicly available counterfactual explanation algorithms on three modern network intrusion datasets. To the best of our knowledge, this work also presents the first comparative analysis of the existing counterfactual explanation algorithms within the context of NIDSs. Our proposed method provides plausible and diverse counterfactual explanations more efficiently than the tested counterfactual algorithms, reducing the time required to generate explanations. We also demonstrate how the proposed method can provide actionable explanations for NIDSs by summarizing them into a set of actionable global counterfactual rules, which effectively filter out incoming attack queries. This ability of the rules is crucial for efficient intrusion detection and defense mechanisms. We have made our implementation publicly available on GitHub.