B-1
Cisco Intrusion Prevention System Sensor CLI Configuration Guide for IPS 7.2
OL-29168-01
APPENDIX
B

Signature Engines

This appendix describes the IPS signature engines, and contains the following sections:
Understanding Signature Engines, page B-1
Master Engine, page B-4
Regular Expression Syntax, page B-9
AIC Engine, page B-10
Atomic Engine, page B-14
Fixed Engine, page B-30
Flood Engine, page B-32
Meta Engine, page B-33
Multi String Engine, page B-35
Normalizer Engine, pageB-36
Service Engines, page B-39
State Engine, page B-60
String Engines, page B-62
String XL Engines, page B-65
Sweep Engines, page B-68
Traffic Anomaly Engine, page B-71
Traffic ICMP Engine, page B-73
Trojan Engines, pageB-74

Understanding Signature Engines

A signature engine is a component of the Cisco IPS that is designed to support many signatures in a
certain category. An engine is composed of a parser and an inspector. Each engine has a set of parameters
that have allowable ranges or sets of values.
Note
The Cisco IPS engines support a standardized Regex.