Abstract Tracing Based Active Intrusion Response Journal of Information Warfare, Vol. 1, No. 1 Xinyuan Wang, Douglas S. Reeves, S. Felix Wu Network-based intrusion has become a serious threat to today’s highly networked information systems, existing intrusion defense approaches such as intrusion prevention, detection, tolerance and response are "passive" in response to network-based intrusions in that their countermeasures are limited to being local to the intrusion target and there is no automated, network-wide counteraction against detected intrusions. While they all play an important role in counteracting network-based intrusion, they do not, however, effectively address the root cause of the problem -- intruders. What is missing from existing intrusion prevention, detection, tolerance and response is an effective way to identify network-based intruders and hold them accountable for their intrusions. Network-based intrusion can not be effectively repelled or eliminated until its source is known. In this paper, we propose Tracing Based Active Intrusion Response (TBAIR) as a new way to address the problem of network-based intrusion. Based on Sleepy Watermark Tracing (SWT), TBAIR is able to effectively trace the detected intrusion that utilizes stepping stone to disguise its origin at real-time, and dynamically push the intrusion countermeasures such as remote monitoring, blocking, containment and isolation close to the source of the intrusion. Through SWT’s unique active watermark technique, TBAIR is able to trace even when the intrusion connection is idle. Therefore it helps to apprehend the intruders on the spot and hold them accountable for their intrusions. Keywords: Network-based Intrusion, Active Intrusion Tracing, Active Intrusion Response.