ProHunter: A Comprehensive APT Hunting System Based on Whole-System Provenance

TL;DR

ProHunter is a system that improves APT threat hunting by efficiently analyzing whole-system provenance graphs, accurately identifying attack patterns, and bridging semantic gaps between threat intelligence and system data.

Contribution

ProHunter introduces a compact data structure, heuristic threat graph sampling, and adaptive graph representation to enhance efficiency and accuracy in provenance-based APT hunting.

Findings

Outperforms state-of-the-art systems in efficiency and accuracy

Effectively extracts precise attack patterns from large provenance graphs

Bridges semantic gaps between CTI reports and system provenance data

Abstract

Advanced Persistent Threats (APTs) remain difficult to detect due to their stealthy nature and long-term persistence. To tackle this challenge, provenance-based threat hunting has gained traction as a proactive defense mechanism. This technique models audit logs as a whole-system provenance graph and searches for subgraphs that match APT patterns recorded in Cyber Threat Intelligence (CTI) reports. However, several limitations persist: 1) significant memory and time overhead due to the extremely large provenance graphs; 2) imprecise segmentation of APT activities from provenance graphs due to their intricate entanglement with benign operations; and 3) poor alignment of attack representations between CTI-derived query graphs and provenance graphs due to their substantial semantic gaps. To address these limitations, this paper presents ProHunter, an efficient and accurate provenance-based APT hunting system with a platform-independent design. To minimize system overhead, ProHunter creates a compact data structure that efficiently stores long-term provenance graphs using semantic abstraction and bit-level hierarchical encoding strategies. To segment APT behaviors, a heuristic-driven threat graph sampling algorithm is designed, which can extract precise attack patterns from provenance graphs. Furthermore, to bridge the semantic gaps between CTI-derived graphs and provenance graphs, ProHunter proposes adaptive graph representation and feature enhancement methods, enabling the extraction of consistent attack semantics at both localized and globalized levels.Extensive evaluations on real-world APT campaigns from DARPA TC E3, E5 and OpTC datasets demonstrate that ProHunter outperforms state-of-the-art threat hunting systems in terms of efficiency and accuracy. Our code is available at https://github.com/xueboQiu/ProHunter.