Abstract: A method of detecting intrusions on a computer includes the step of identifying an internet protocol field range describing fields within internet protocol packets received by a computer. A connectivity range is also established which describes a distribution of network traffic received by the computer. An internet protocol field threshold and a connectivity threshold are then determined from the internet protocol field range and connectivity range, respectively. During the operation of the computer, values are calculated for the internet protocol field range and connectivity range. These values are compared to the internet protocol metric threshold and connectivity metric threshold so as to identify an intrusion on the computer.

Abstract: A method of forming a virtual intrusion detection system includes the step of positioning a set of sensors in a network environment, each sensor supporting multiple logical traffic paths. The method also includes the step of providing a set of sensor management systems corresponding to the set of sensors. This set of sensor management systems enforces a set of virtual intrusion detection systems, wherein each virtual intrusion detection system corresponds to a predetermined logical traffic path through the set of sensors, each virtual detection system providing sensor traffic information solely to authorized parties.

Abstract: An intrusion tolerant communication network and related methods is provided that places emphasis on continuity of operation and provides for an attack-survivable communication network whose network devices collectively accomplish the specified networking intent even under attack and despite active intrusions. The present invention defines methods for network intrusion tolerance in terms of the various state transitions that maximize the overall effectiveness of an intrusion tolerant communication network.

Abstract: Methods and apparatuses are described for inspecting data packets in a computer network. One or more data packets through the network have associated header data and content. One method includes receiving a data packet, examining the data packet to classify the data packet including classifying the data packet using information included in the header and content, determining flow instructions for processing the packet based on both the header information and the content and processing of the packet using the flow instructions.

Abstract: An intrusion signature describing an attack is stored on a computer. Once a plurality of internet protocol packets is received, the plurality of internet protocol packets collectively containing an information sequence within a series of states, it is rearranged so as to place the information sequence in order. Each state of the series of states is then successively examined so as to correlate the information sequence to the intrusion signature.

Abstract: A method of provisioning a computer against computer attacks includes constructing a hierarchy characterizing different computer attacks and counter measures, and traversing this hierarchy to identify computer attacks and countermeasures relevant to a target platform. Detection and protection measures are collected in response to this traversing. These detection and protection measures are then downloaded to a security sensor associated with the target platform.

Abstract: A method of adaptively classifying information using a binary tree comprises establishing a binary tree including a set of binary sequences each representing one or more network addresses. Once network traffic is received having identifiers describing network traffic sources, the identifiers are correlated to binary sequences within the binary tree. A revision metric is formed based on this correlating, and the binary tree is then revised according to this revision metric. A method of blocking a DDOS attack comprises establishing a binary tree including a set of binary sequences, each of these binary sequences representing one or more network addresses. When network traffic is received having identifiers describing network traffic sources, the identifiers are correlated to binary sequences within the binary tree. Once a DDOS attack notification signal is received, a selected binary tree path within the binary tree is identified as a low cost blocking path within the binary tree.

Abstract: The invention relates to a reconfigurable scalable intrusion-tolerant network that is interposed between a service requesting client and a protected server to minimize the impact of intrusive events. The apparatus may include a proxy server for receiving the requests from a client and forwarding them to a protected server. Acceptance monitors receive the response from a protected server and apply one or more acceptance tests. A ballot monitor receives the result of the acceptance tests and determines a response to the client. The network may also include an intrusion sensor to detect threats to the network and a reconfigurer to alter the network forwarding scheme. Reconfiguration may include isolating network elements, creating parallel paths, implementing redundant operations, or assessing the validity of responses.

Abstract: A method of detecting intrusions on a computer includes the step of identifying an internet protocol field range describing fields within internet protocol packets received by a computer. A connectivity range is also established which describes a distribution of network traffic received by the computer. An internet protocol field threshold and a connectivity threshold are then determined from the internet protocol field range and connectivity range, respectively. During the operation of the computer, values are calculated for the internet protocol field range and connectivity range. These values are compared to the internet protocol metric threshold and connectivity metric threshold so as to identify an intrusion on the computer.

Abstract: An intrusion tolerant communication network and related methods is provided that places emphasis on continuity of operation and provides for an attack-survivable communication network whose network devices collectively accomplish the specified networking intent even under attack and despite active intrusions. The present invention defines methods for network intrusion tolerance in terms of the various state transitions that maximize the overall effectiveness of an intrusion tolerant communication network.

Abstract: A method of detecting intrusions on a computer includes storing an intrusion signature describing an attack on a computer. Once a plurality of internet protocol packets is received, the plurality of internet protocol packets collectively containing an information sequence within a series of states, it is rearranged so as to place the information sequence in order. Each state of the series of states is then successively examined so as to correlate the information sequence to the intrusion signature.

Abstract: A method of detecting intrusions on a computer includes the step of identifying an internet protocol field range describing fields within internet protocol packets received by a computer. A connectivity range is also established which describes a distribution of network traffic received by the computer. An internet protocol field threshold and a connectivity threshold are then determined from the internet protocol field range and connectivity range, respectively. During the operation of the computer, values are calculated for the internet protocol field range and connectivity range. These values are compared to the internet protocol metric threshold and connectivity metric threshold so as to identify an intrusion on the computer.

Abstract: A method of provisioning a computer against computer attacks includes constructing a hierarchy characterizing different computer attacks and counter measures, and traversing this hierarchy to identify computer attacks and countermeasures relevant to a target platform. Detection and protection measures are collected in response to this traversing. These detection and protection measures are then downloaded to a security sensor associated with the target platform.

Abstract: A method of forming a virtual intrusion detection system includes the step of positioning a set of sensors in a network environment, each sensor supporting multiple logical traffic paths. The method also includes the step of providing a set of sensor management systems corresponding to the set of sensors. This set of sensor management systems enforces a set of virtual intrusion detection systems, wherein each virtual intrusion detection system corresponds to a predetermined logical traffic path through the set of sensors, each virtual detection system providing sensor traffic information solely to authorized parties.

Abstract: The invention relates to a reconfigurable scalable intrusion-tolerant network that is interposed between a service requesting client and a protected server to minimize the impact of intrusive events. The apparatus may include a proxy server for receiving the requests from a client and forwarding them to a protected server. Acceptance monitors receive the response from a protected server and apply one or more acceptance tests. A ballot monitor receives the result of the acceptance tests and determines a response to the client. The network may also include an intrusion sensor to detect threats to the network and a reconfigurer to alter the network forwarding scheme. Reconfiguration may include isolating network elements, creating parallel paths, implementing redundant operations, or assessing the validity of responses.