Abstract:
There has been an increasing number of attacks against critical water system infrastructure in
recent years. This is largely due to the fact that these systems are heavily dependent on computer networks
meaning that an attacker can use conventional techniques to penetrate this network which would give
them access to the supervisory control and data acquisition (SCADA) system. The devastating impact of
a successful attack in these critical infrastructure applications could be long-lasting with major social and
financial implications. Intrusion detection systems are deployed as a secondary defence mechanism in case an
attacker is able to bypass the systems preventative security mechanisms. In this thesis, behavioural intrusion
detection is addressed in the context of detecting cyber-attacks in water distribution systems. A comparative
analysis of various predictive neural network architectures is conducted and from this a novel voting-based
ensemble technique is presented. Finally an analysis of how this approach to behavioural intrusion detection
can be enhanced by both univariate and multivariate outlier detection techniques It was found that multiple
algorithms working together are able to counteract their limitation to produce a more robust algorithm with
improved results.
