Modeling and detection of the multi-stages of Advanced Persistent Threats attacks based on semi-supervised learning and complex networks characteristics

Abstract Advanced Persistent Threats (APT) present the most sophisticated types of attacks to modern networks which have proved to be very challenging to address. Using sophisticated attack techniques, attackers remotely control infected machines and exfiltrate sensitive information from organizations and governments. Security products deployed by enterprise networks based on traditional defenses often fail at detecting APT infections because of the dynamic nature of the APT attack process. To overcome the current limitations of attack network dynamics faced in APT studies, an innovative APT attack detection model based on a semi-supervised learning approach and complex networks characteristics is proposed in this paper. The entire targeted network is modeled as a small-world network and the evolving APT-Attack Network (APT-AN) as a scale-free network. Finite state machines are employed to model the state transitions of the nodes in the time domain in order to characterize the state changes during the APT attack process. The effectiveness of the model is demonstrated by applying it to real-world data from a large-scale enterprise network consisting of 17,684 hosts from the Los Alamos security lab. The proposed approach analyzes efficiently the large-scale dataset to reveal APT attack characteristics between the command and control center and the victim hosts. The final result is a ranked list of suspicious hosts participating in APT attack activities. The average detection precision of three APT stage is 90.5% in our proposed APT detection framework. The results show that the model can effectively detect the suspicious hosts at different stages of the APT attack process.