Abstract: A method for determining the entry point of an attack by a vandal such as a hacker upon a device such as a computer or a server such as a web server that operates under the protection of an intrusion detection system. Intrusion detection information regarding the attack and network information regarding the attack are correlated, and the entry point of the attack thereby deduced. In one embodiment, a source address of a message representative of the attack is found in a router table of a router that provides a connection supporting the attack. Logical ports of the connection are determined, and the corresponding physical ports found, thereby identifying the attack's entry point into the protected device.

Abstract: Method, system, and program product for port based authentication protocols where addresses are dynamically assigned within a network environment, and more particularly to port based authentication in the network environment, where connection information is captured and stored. This facilitates administrator access to information created as a result of protocol exchanges involved in dynamic address assignment, authentication, and connection.

Abstract: A method of operating an intrusion detection system. The system determines occurrence of a signature event indicative of a denial of service intrusion on a protected device. A value of a signature event counter is increased. The value of the signature event counter is adjusted to not include a count of signature events past a sliding window. The value of the signature event counter is determined to exceed a signature threshold quantity, followed by generation of an alert at a time subsequently recorded in a log. The log is cleared of entries past a permissible age. A present alert generation rate is determined as a ratio of the total number of timestamps in the log to the permissible age. The present alert generation rate is ascertained to exceed an alert generation rate threshold. A selected element of the signature set is altered to decrease the alert generation rate.

Abstract: An intrusion detection system is improved by altering its signatures and thresholds during a denial of service attack, in order to decrease the rate at which an intrusion detection sensor sends alerts to an intrusion detection server. A governor within the sensor is associated with each signature. The governor may include an alert log, a timer, an alert-generation-rate threshold, and rules that prescribe actions to be taken when the alert-generation-rate threshold is exceeded. The governor records the generation time of each alert by the sensor, and determines the rate at which the sensor is presently generating alerts. When the present alert-generation rate exceeds the alert-generation-rate threshold, the governor alters the associated signature threshold to decrease the alert generation rate of the intrusion detection sensor.

Abstract: Performance of a pattern-matching intrusion detection system (IDS) is improved by ranking signatures in its signature table by likelihood of occurrence, so that the table may be searched efficiently. Occurrence data associated with signatures is kept, and the ranking adaptively revised according to updates of the data. When the IDS detects a system event, the signature table is searched. If the search does not find a signature matching the event, thereby suggesting that the event poses no threat, a null signature is added to the signature table in a strategic location to terminate future searches early. In one embodiment, null signatures may be stored in a cache. When a system event is detected, the cache is searched. If a match is not found, the signature table is searched. If a match is not found in the signature table, a null signature is cached.

Abstract: An intrusion detection system checks a list of business rules at predetermined update times, and determines whether any provision of the business rules has become newly operative since the last update time. Provisions of the business rules prescribe alterations to intrusion signatures, thresholds, actions, or weights that are appropriate to broader circumstances evident at the update time. Whenever a new provision is found to be operative, the effected signatures, thresholds, actions, or weights are altered accordingly.

Abstract: An intrusion detection system monitors for signature events, which are part of base intrusion sets that include signature event counters, signature thresholds, and base actions. Associated with each base intrusion set is an action set including an action counter, an action threshold, and an action variable. The associated action counter is updated when the base action of the base intrusion set is invoked responsive to the count of associated signature events meeting the associated signature threshold. The action counter is compared with an action threshold. If the action counter meets the threshold, the associated action variable is updated. The action variable is then passed to an analysis engine comprising a set of rules, which analyses the action variable either in isolation or together with other action variables associated with other base intrusion sets. According to the analysis, an element of a base intrusion set or an action set may be changed.

Abstract: Performance of a pattern-matching intrusion detection system (IDS) is improved by ranking signatures in its signature table by likelihood of occurrence, so that the table may be searched efficiently. Occurrence data associated with signatures is kept, and the ranking adaptively revised according to updates of the data. When the IDS detects a system event, the signature table is searched. If the search does not find a signature matching the event, thereby suggesting that the event poses no threat, a null signature is added to the signature table in a strategic location to terminate future searches early. In one embodiment, null signatures may be stored in a cache. When a system event is detected, the cache is searched. If a match is not found, the signature table is searched. If a match is not found in the signature table, a null signature is cached.

Abstract: An intrusion detection system is improved by altering its signatures and thresholds during a denial of service attack, in order to decrease the rate at which an intrusion detection sensor sends alerts to an intrusion detection server. A governor within the sensor is associated with each signature. The governor may include an alert log, a timer, an alert-generation-rate threshold, and rules that prescribe actions to be taken when the alert-generation-rate threshold is exceeded. The governor records the generation time of each alert by the sensor, and determines the rate at which the sensor is presently generating alerts. When the present alert-generation rate exceeds the alert-generation-rate threshold, the governor alters the associated signature threshold to decrease the alert generation rate of the intrusion detection sensor.

Abstract: A method for determining the entry point of an attack by a vandal such as a hacker upon a device such as a computer or a server such as a web server that operates under the protection of an intrusion detection system. Intrusion detection information regarding the attack and network information regarding the attack are correlated, and the entry point of the attack thereby deduced. In one embodiment, a source address of a message representative of the attack is found in a router table of a router that provides a connection supporting the attack. Logical ports of the connection are determined, and the corresponding physical ports found, thereby identifying the attack's entry point into the protected device.

Abstract: An intrusion detection system monitors for signature events, which are part of base intrusion sets that include signature event counters, signature thresholds, and base actions. Associated with each base intrusion set is an action set including an action counter, an action threshold, and an action variable. The associated action counter is updated when the base action of the base intrusion set is invoked responsive to the count of associated signature events meeting the associated signature threshold. The action counter is compared with an action threshold. If the action counter meets the threshold, the associated action variable is updated. The action variable is then passed to an analysis engine comprising a set of rules, which analyses the action variable either in isolation or together with other action variables associated with other base intrusion sets. According to the analysis, an element of a base intrusion set or an action set may be changed.

Abstract: An intrusion detection system checks a list of business rules at predetermined update times, and determines whether any provision of the business rules has become newly operative since the last update time. Provisions of the business rules prescribe alterations to intrusion signatures, thresholds, actions, or weights that are appropriate to broader circumstances evident at the update time. Whenever a new provision is found to be operative, the effected signatures, thresholds, actions, or weights are altered accordingly.