All ASA models should be able to accommodate for this using a specific enough regex string within an inspect class-map riding in an http inspect policy-map. You'd have to know what you are looking for to match with regex, whose config lines are limited to 100-something chars. For something more scalable and configurable, a full-fledged IPS would probably be preferred.
You might also take a look at the ACE Web Application Firewall (WAF). This product is specifically designed for protecting websites against attacks like this (and a number of other web specific attacks).
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...