An effective unsupervised network anomaly detection method

In this paper, we present an effective tree based subspace clustering technique (TreeCLUS) for finding clusters in network intrusion data and for detecting unknown attacks without using any labelled traffic or signatures or training. To establish its effectiveness in finding all possible clusters, we perform a cluster stability analysis. We also introduce an effective cluster labelling technique (CLUSLab) to generate labelled dataset based on the stable cluster set generated by TreeCLUS. CLUSLab is a multi-objective technique that exploits an ensemble approach for stability analysis of the clusters generated by TreeCLUS. We evaluate the performance of both TreeCLUS and CLUSLab in terms of several real world intrusion datasets to identify unknown attacks and find that both outperform the competing algorithms.