SRI Security Research Institute, Edith Cowan University, Perth, Western Australia
The literature reviewed suggests that Network Intrusion Systems (NIDS) are valuable tools for the detection of malicious behaviour in network environments. NIDS provide alerts and the trigger for rapid responses to attacks. Our previous research had shown that NIDS performance in wireless networks had a wide variation under different workloads. In this research we chose wired networks and asked the question: What is the evidential value of NIDS? Three different NIDS were tested under two different attacks and with six different packet rates. The results were alarming. As the work loading increased the NIDS detection capability fell rapidly and as the complexity of attack increased the NIDS detection capability fell more quickly. We conclude that NIDS have weak evidential value for either system improvement or legal admissibility.