SHIELD: APT Detection and Intelligent Explanation Using LLM

Advanced persistent threats (APTs) are sophisticated cyber attacks that can remain undetected for extended periods, making their mitigation particularly challenging. Given their persistence, significant effort is required to detect them and respond effectively. Existing provenance-based attack detection methods often lack interpretability and suffer from high false positive rates, while investigation approaches are either supervised or limited to known attacks. To address these challenges, we introduce SHIELD, a novel approach that combines statistical anomaly detection and graph-based analysis with the contextual analysis capabilities of large language models (LLMs). SHIELD leverages the implicit knowledge of LLMs to uncover hidden attack patterns in provenance data, while reducing false positives and providing clear, interpretable attack descriptions. This reduces analysts' alert fatigue and makes it easier for them to understand the threat landscape. Our extensive evaluation demonstrates SHIELD's effectiveness and computational efficiency in real-world scenarios. SHIELD was shown to outperform state-of-the-art methods, achieving higher precision and recall. SHIELD's integration of anomaly detection, LLM-driven contextual analysis, and advanced graph-based correlation establishes a new benchmark for APT detection.