As the communication industry has connected distant corners of the globe using advances in network technology, intruders or attackers have also increased attacks on networking infrastructure commensurately. System administrators can attempt to preven
t such attacks using intrusion detection tools and systems. There are many commercially available signature-based Intrusion Detection Systems (IDSs). However, most IDSs lack the capability to detect novel or previously unknown attacks. A special type of IDSs, called Anomaly Detection Systems, develop models based on normal system or network behavior, with the goal of detecting both known and unknown attacks. Anomaly detection systems face many problems including high rate of false alarm, ability to work in online mode, and scalability. This paper presents a selective survey of incremental approaches for detecting anomaly in normal system or network traffic. The technological trends, open problems, and challenges over anomaly detection using incremental approach are also discussed.
