  The immune system provides a rich metaphor for computer security: anomaly
detection that works in nature should work for machines. However, early
artificial immune system approaches for computer security had only limited
success. Arguably, this was due to these artificial systems being based on too
simplistic a view of the immune system. We present here a second generation
artificial immune system for process anomaly detection. It improves on earlier
systems by having different artificial cell types that process information.
Following detailed information about how to build such second generation
systems, we find that communication between cells types is key to performance.
Through realistic testing and validation we show that second generation
artificial immune systems are capable of anomaly detection beyond generic
system policies. The paper concludes with a discussion and outline of the next
steps in this exciting area of computer security.
