A Framework for Cyber Threat Intelligence Extraction from Raw Log Data

Intrusion Detection Systems (IDS) rely on the availability and correctness of Indicators of Compromise (IoC), i.e., artifacts such as IP addresses that are known to correspond to malicious system activities. However, the simple nature and limited validity of these indicators impairs protection against cyber threats. Tactics, Techniques and Procedures (TTP) provide abstract information on attacker behavior, but are only available in human-readable format that prevents automatic detection using IDSs. In this paper we therefore propose an approach that extracts cyber threat intelligence from raw log data and combines the advantages of IoCs and TTPs by producing detectable patterns of complex system behavior. Other than existing approaches, our approach employs log data anomaly detection to disclose suspicious log events, which are used for iterative clustering, pattern recognition, and refinement. Our evaluations show that automatically extracted threat intelligence corresponding to a multi-step attack is suitable for detection of the same attack on another system.