An analysis of correlations of intrusion alerts in an NREN

An ever increasing impact and amount of network attacks have driven many organizations to deploy various network monitoring and analysis systems such as honeypots, intrusion detection systems, log analyzers and flow monitors. Besides improving these systems a logical next step is to collect and correlate alerts from multiple systems distributed across organizations. The idea is to leverage a joint effect of multiple monitoring systems to build a more robust and efficient system, ideally, lacking the shortcomings of the individual contributing systems. This paper presents an analysis of alert reports gathered from several such detectors deployed in national research and education network (NREN). The analysis focuses on the correlations of reported events in temporal domain as well as on the correlations of different event types.