Edinburgh Napier University

  Cyber crimes and malicious network activities have posed serious threats to the entire internet and its users. This issue is becoming more critical, as network-based services, are more widespread and closely related to our daily life. Thus, it has raised a serious concern in individual internet users, industry and research community. A significant amount of work has been conducted to develop intelligent anomaly-based intrusion detection systems (IDSs) to address this issue. However, one technical challenge, namely reducing false alarm, has been along with the development of anomaly-based IDSs since 1990s. In this paper, we provide a solution to this challenge. A nonlinear correlation coefficient-based (NCC) similarity measure is proposed to help extract both linear and nonlinear correlations between network traffic records. This extracted correlative information is used in our proposed IDS to detect malicious network behaviours. The effectiveness of the proposed NCC-based measure and the proposed IDS are evaluated using NSL-KDD dataset. The evaluation results demonstrate that the proposed NCC-based measure not only helps reduce false alarm rate, but also helps discriminate normal and abnormal behaviours efficiently.