ClusterFA: a memory-efficient DFA structure for network intrusion detection

Network intrusion detection systems (NIDS) plays an increasing important role in the field of network security. Current NIDS, such as Bro and Snort, mainly use signatures to represent and detect networking attacks. Traditionally the signatures are depicted by exact string patterns. However, new worms and viruses emerge endlessly in recent years. As a result, the scale of signatures increases sharply. Compared with exact strings, regular expressions have more powerful expressiveness, and are replacing exact strings gradually in state-of-the-art NIDS.