Danger Theory and Intrusion Detection: Possibilities and Limitations of the Analogy

Metaphors derived from Danger Theory, a hypothesized model of how the human immune system works, have been applied to the intrusion detection domain. The major contribution in this area, is the dendritic cell algorithm (DCA). This paper presents an in-depth analysis of results obtained from two previous experiments, regarding the suitability of the danger theory analogy in constructing intrusion detection systems for web applications. These detectors would be capable of detecting novel attacks while improving on the limitations of anomaly-based intrusion detectors. In particular, this analysis investigates which aspects of this analogy are suitable for this purpose, and which aspects of the analogy are counterproductive if utilized in the way originally suggested by danger theory. Several suggestions are given for those aspects of danger theory that are identified to require modification, indicating the possibility of further pursuing this approach. These modifications could be realized in terms of developing a robust signal selection schema and a suitable correlation algorithm. This would allow for an intrusion detection approach that has the potential to overcome those limitations presently associated with existing techniques.