i think for writing the regular expressions corresponding to an attack would be too much of configuraiton.
I would suggest enabling default signatures on asa using ip audit commands.
that would take care of most frequently seen attacks.
now,to be safe against every new attack which come out,f/w would need an aip-ssm module in it.the intrusion prevention module can defend the network against any known attack.it has a huge database of signatures which get updates regularly on cisco website.
Table of ContentsIntroductionVersion HistoryPossible Future
UpdatesDocuments PurposeNAT Operation in ASA 8.3+ SectionsRule Types
Network Object NATTwice NAT / Manual NATRule Types used per SectionNAT
Types used with Twice NAT / Manual NAT and Network Obje...
Table of Contents Introduction:This document describes details on how
NAT-T works. Background: ESP encrypts all critical information,
encapsulating the entire inner TCP/UDP datagram within an ESP header.
ESP is an IP protocol in the same sense that TCP an...