Enterasys Intrusion Prevention System Manual page 167

Creating Custom Signatures
Extended Pattern
The extended signature language contains an expanded variation for the original definition of a
pattern on which to search. This new definition allows such a pattern to take into account
URL-encoded data with the URI Decode attribute. It still follows the same "/0a" notation used for
Basic signatures for specifying hex codes to search for in network traffic (described in "Specifying
Signature Pattern Strings" on page 3-18).
The following example illustrates the usage of the Extended Pattern Type to match the hex code
"/01".
Creating Network Sensor Policies and Signatures 3-25