8. Conclusions
We have proposed the first framework that is able to identify and rank suspicious hosts possibly involved in data exfiltrations related to APTs. Our approach gathers and analyzes only network traffic data. We propose a set of features that is specifically tailored to detect possible data exfiltrations, and we define a suspiciousness score for each internal host. The final output is a ranked list of suspicious hosts possibly involved in data exfiltrations and other APT-related activities. The effectiveness of the proposed solution has been proved by implementing a prototype that is deployed on a real large network environment. The proposed approach is able to analyze about 140 millions of flows related to approximately 10,000 internal hosts in about 2 minutes. Experimental results demonstrate the ability of the framework to identify burst and low-and-slow exfiltrations. Our proposal paves the way to novel forms of efficient and automated traffic analyses related to APT activities. Future work includes the integration of correlation systems with respect to other network security assets, such as data flows and alerts coming from intrusion detection systems.