Towards Practical Anomaly-based Intrusion Detection by Outlier Mining on TCP Packets

Abstract. Intrusion detection System (IDS) is an important part of the security of large networks like the Internet. With increasing number of data being transmitted day by day from one subnetwork to another, the system needs to identify intrusion in such large datasets in an effectively and timely manner. So the application of knowledge discovery comes handy to identify unusual accesses or attacks. Improving an IDS’s per-formance and accuracy is one of the major challenges network security research today. In this paper, we propose a practical anomaly-based IDS using outlier mining of the readily available basic Transmission Control Protocol (TCP) header information as well as other easily derivable at-tributes. We use a two-step approach of k-means clustering and one-class support vector machine (SVM) to model the normal sessions presented in MIT DARPA ’99 dataset. We then feed the testing set to the resultant model to predict the attacks sessions