  Network Intrusion Detection Systems (NIDS) are computer systems which monitor
a network with the aim of discerning malicious from benign activity on that
network. While a wide range of approaches have met varying levels of success,
most IDSs rely on having access to a database of known attack signatures which
are written by security experts. Nowadays, in order to solve problems with
false positive alerts, correlation algorithms are used to add additional
structure to sequences of IDS alerts. However, such techniques are of no help
in discovering novel attacks or variations of known attacks, something the
human immune system (HIS) is capable of doing in its own specialised domain.
This paper presents a novel immune algorithm for application to the IDS
problem. The goal is to discover packets containing novel variations of attacks
covered by an existing signature base.
