Cisco Technology, Inc.

Thomas E Bernhard

Gerald S Lathem

Steven Dale Shanklin

A method of describing intrusion signatures, which are used by an intrusion detection system to detect attacks on a local network. The signatures are described using a &ldquo;high level&rdquo; syntax having features in common with regular expression and logical expression methodology. These high level signatures may then be compiled, or otherwise analyzed, to provide a process executable by a sensor or other processor-based signature detector.

Intrusion detection signature analysis using regular expressions and logical operators

A method of detecting signatures representing misuse of a local network. Known reference signatures having one or more common events are identified, and represented with a decision graph having one or more shared nodes. Each node of the decision graph represents the occurrence of an event. Given a set of input events, test functions associated with nodes determine the path taken during traversal of the graph. A path of the graph from the parent node to a leaf node represents the occurrence of all events that comprise a signature. The decision graph permits any of the signatures to be detected with only one traversal, and avoids the need for a separate matching process for each signature. In this manner, an entire set of all known reference signatures may be consolidated into a smaller set of decision graphs.

Growing community of inventors

Round Rock, TX, United States of America

Thomas E Bernhard