This paper provides a general and comprehensive approach to implementing misuse detection on expert systems and an in-depth analysis of the effectiveness of the optimization strategies of the Rete algorithm wrt. the general implementation approach. General efficiency limits of Retebased expert systems in the domain of misuse detection are determined analytically and validated experimentally. We conclude that expert systems may still have their merit in rapid prototyping of misuse detection IDSs, but they should not be considered for modern production systems.