Network Anomaly Detection in the Cloud: The Challenges of Virtual Service Migration

The use of virtualisation technology in the cloud enables services to migrate within and across geographically diverse data centres, e.g., to enable load balancing and fault tolerance. An important part of securing cloud services is being able to detect anomalous behaviour, caused by attacks, that is evident in network traffic. However, it is not clear whether virtual service migration adversely affects the performance of contemporary network-based anomaly detection approaches. In this paper, we explore this issue, and show that wide-area virtual service migration can adversely affect state of the art approaches to network flow-based anomaly detection techniques, potentially rendering them unusable.