Cylant, Inc.

Reflex Security, Inc.

John C Munson

Sebastian G Elbaum

A real-time approach for detecting aberrant modes of system behavior induced by abnormal and unauthorized system activities that are indicative of an intrusive, undesired access of the system. This detection methodology is based on behavioral information obtained from a suitably instrumented computer program as it is executing. The theoretical foundation for the present invention is founded on a study of the internal behavior of the software system. As a software system is executing, it expresses a set of its many functionalities as sequential events. Each of these functionalities has a characteristic set of modules that is executed to implement the functionality. These module sets execute with clearly defined and measurable execution profiles, which change as the executed functionalities change. Over time, the normal behavior of the system will be defined by the boundary of the profiles. An attempt to violate the security of the system will result in behavior that is outside the normal activity of the system and thus result in a perturbation of the system in a manner outside the scope of the normal profiles. Such violations are detected by an analysis and comparison of the profiles generated from an instrumented software system against a set of known intrusion profiles and a varying criterion level of potential new intrusion events.

Method of and system for detecting an anomalous operation of a computer system

Detecting abnormal activity of a software system is based on behavioral information obtained from an instrumented computer program while it executes. As the program executes, it expresses information about the sequence and frequency with which program modules are called. Over time, this sequence and frequency defines the normal behavior of the program, and the information expressed on any given run is compared to this normal behavior. Statistical analysis of the differences between the normal behavior and the current run can be used to detect unauthorized or abusive use of the program. Program modules whose behavior is highly correlated can be grouped into a smaller number of virtual modules. Comparison between current and normal program behavior can then be made on the (smaller number of) virtual modules, thereby reducing the dimensionality of the problem of analyzing the differences between current and normal program behavior.

Method and system for establishing normal software system behavior and departures from normal behavior

A real-time approach to detecting aberrant modes of system behavior induced by abnormal and unauthorized system activities indicative of abnormal activity of a software system is based on behavioral information obtained from a suitably instrumented computer program as it is executing. The theoretical foundation is founded on a study of the internal behavior of the software system. As a software system is executing, it expresses a set of its many functionalities as sequential events. Each of these functionalities has a characteristic set of modules that is executed to implement the functionality. These module sets execute with defined and measurable execution profiles among the program modules and within the execution paths of the individual modules, which change as the executed functionalities change. Over time, the normal behavior of the system will be defined by the boundary of the profiles. Abnormal activity of the system will result in behavior that is outside the normal activity of the system and thus result in a perturbation of the system in a manner outside the scope of the normal profiles. Such anomalies are detected by analysis and comparison of the profiles generated from an instrumented software system against a set of nominal execution profiles. Moreover, a method for reducing the amount of information necessary to understand the functional characteristics of an executing software system identifies the common sources of variation among the program instrumentation point frequencies and builds execution profiles based on a reduced set of virtual execution domains.

Growing community of inventors

Moscow, ID, United States of America

John C Munson