Abstract: A method of determining correlated flows in a network may include obtaining times of arrival and corresponding flows for data units in the network (1020) and assigning weights to a set of data units based on respective times between the set of data units and one data unit (1030). A probability matrix representing interflow connections in the network may be updated based on the assigned weights (1040).

Abstract: A method and system is provided for detecting correlated connections in an extended connection. A plurality of stepping stone detection algorithms are executed in parallel (400), each of the plurality of stepping stone detection algorithms generating a result. The results are scored for each of the plurality of stepping stone detection algorithms (402). A consensus attack path is generated based upon the scored results (404).

Abstract: A system and method for determining the point of entry of a malicious packet into a network is disclosed. An intrusion detection system detects entry of the malicious packet into the network (500). A stepping stone detection system identifies stepping stones in extended connections within the network (524). A traceback engine isolates the malicious packet in response to operation of the intrusion detection system (528), wherein the traceback engine utilizes the identified stepping stones to determine the point of entry of the malicious packet.

Abstract: A system (200) detects transmission of potentially malicious packets. The system (200) receives, or otherwise observes, packets and generates hash values based on variable-sized blocks of the packets. The system (200) then compares the generated hash values to hash values associated with prior packets. The system (200) determines that one of the received packets is a potentially malicious packet when one or more of the generated hash values associated with the received packet match one or more of the hash values associated with the prior packets.

Abstract: A network analysis architecture provides a suite of complementary logic operable at different temporal and spatial timescales. The distinct temporal and spatial scales define different tiers, each analyzing network events according to predetermined temporal and spatial scales of progressive magnitude. Particular event detection logic may be operable on an immediate temporal scale, while other logic identifies trends over a longer time period. Similarly, different spatial scales are appropriate to different algorithms, as in logic that examines only headers or length of packets, or inspects an entire payload or transferred file. Deployment of logic that is focused on different timing and scope of data allows timely action in the case of readily apparent deviations, and permits longer term analysis for identifying trends that emerge over time.

Abstract: A system (120) detects transmission of potentially unwanted e-mail messages. The system (120) may receive e-mail messages and generate hash values based on one or more portions of the e-mail messages. The system (120) may then determine whether the generated hash values match hash values associated with prior e-mail messages. The system (120) may determine that one of the e-mail messages is a potentially unwanted e-mail message when one or more of the generated hash values associated with the e-mail message match one or more of the hash values associated with the prior e-mail messages.

Abstract: A system (126-129) detects transmission of potentially malicious packets. The system (126-129) receives packets and generates hash values corresponding to each of the packets. The system (126-129) may then compare the generated hash values to hash values corresponding to prior packets. The system (126-129) determines that one of the packets is a potentially malicious packet when the generated hash value corresponding to the one packet matches one of the hash values corresponding to one of the prior packets and the one prior packet was received within a predetermined amount of time of the one packet. The system (126-129) may also facilitate the tracing of the path taken by a potentially malicious packet. In this case, the system (126-129) may receive a message that identifies a potentially malicious packet, generate hash values from the potentially malicious packet, and determine whether one or more of the generated hash values match hash values corresponding to previously-received packets.

Abstract: A system and method for performing source path isolation in a network. The system comprises an intrusion detection system (IDS), a source path isolation server (SS1) and at least one router configured to operate as a source path isolation router (SR1) operating within an autonomous system. When IDS detects a malicious packet, a message is sent to SS1. SS1 in turn generates a query message (QM) containing at least a portion of the malicious packet. Then, QM is sent to participating routers located one hop away. SR1 uses the query message to determine if it has observed the malicious packet by comparing it with locally stored information about packets having passed through SR1. SR1 sends a reply to SS1, and SS1 uses the reply to identify the ingress point into the network of the malicious packet.

Abstract: A system and method for performing source path isolation in a network. The system comprises an intrusion detection system (IDS), a source path isolation server (SS1) and at least one router configured to operate as a source path isolation router (SR1) operating within an autonomous system. When IDS detects a malicious packet, a message is sent to SS1. SS1 in turn generates a query message (QM) containing at least a portion of the malicious packet. Then, QM is sent to participating routers located one hop away. SR1 uses the query message to determine if it has observed the malicious packet by comparing it with locally stored information about packets having passed through SR1. SR1 sends a reply to SS1, and SS1 uses the reply to identify the ingress point into the network of the malicious packet.

Abstract: A system and method for identifying target packets in a network. The invention identifies packets by computing a hash value over at least a portion of a packet passing through a network device such as a router. The hash value is used as an address, or index, into a memory. The hash value identifies a unique memory address and a flag is set at the respective memory location. When a target packet is detected elsewhere in a network, the network device receives a query message containing a hash value of the target packet. The network device compares the target packet to the hash values in memory. A match between the hash value in memory and the hash value in the query message indicates the target packet was observed by the network device. After a match is detected, the network device makes a reply available to the network.

Abstract: A system (200) detects transmission of potentially malicious packets. The system (200) receives, or otherwise observes, packets and generates hash values based on variable-sized blocks of the packets. The system (200) then compares the generated hash values to hash values associated with prior packets. The system (200) determines that one of the received packets is a potentially malicious packet when one or more of the generated hash values associated with the received packet match one or more of the hash values associated with the prior packets.

Abstract: A system (126-129) detects transmission of potentially malicious packets. The system (126-129) receives packets and generates hash values corresponding to each of the packets. The system (126-129) may then compare the generated hash values to hash values corresponding to prior packets. The system (126-129) determines that one of the packets is a potentially malicious packet when the generated hash value corresponding to the one packet matches one of the hash values corresponding to one of the prior packets and the one prior packet was received within a predetermined amount of time of the one packet. The system (126-129) may also facilitate the tracing of the path taken by a potentially malicious packet. In this case, the system (126-129) may receive a message that identifies a potentially malicious packet, generate hash values from the potentially malicious packet, and determine whether one or more of the generated hash values match hash values corresponding to previously-received packets.

Abstract: A system (120) detects transmission of potentially unwanted e-mail messages. The system (120) may receive e-mail messages and generate hash values based on one or more portions of the e-mail messages. The system (120) may then determine whether the generated hash values match hash values associated with prior e-mail messages. The system (120) may determine that one of the e-mail messages is a potentially unwanted e-mail message when one or more of the generated hash values associated with the e-mail message match one or more of the hash values associated with the prior e-mail messages.

Abstract: A system (120) detects transmission of potentially unwanted e-mail messages. The system (120) may receive e-mail messages and generate hash values based on one or more portions of the e-mail messages. The system (120) may then determine whether the generated hash values match hash values associated with prior e-mail messages. The system (120) may determine that one of the e-mail messages is a potentially unwanted e-mail message when one or more of the generated hash values associated with the e-mail message match one or more of the hash values associated with the prior e-mail messages.

Abstract: A system (120) detects transmission of potentially unwanted e-mail messages. The system (120) may receive e-mail messages and generate hash values based on one or more portions of the e-mail messages. The system (120) may then determine whether the generated hash values match hash values associated with prior e-mail messages. The system (120) may determine that one of the e-mail messages is a potentially unwanted e-mail message when one or more of the generated hash values associated with the e-mail message match one or more of the hash values associated with the prior e-mail messages.

Abstract: A system for passively analyzing an aggregation of communication signals simultaneously passing through a network link performs spectral analysis on a trace of communication traffic through the network link. The spectral analysis identifies period components of the trace corresponding to different communication signals. A system for deterring the passive analysis of signals aggregates communication traffic through a network link, such that a plurality of signals simultaneously pass through the network link. The plurality of signals is regulated such that the data packets corresponding to the plurality of signals leave the network link at a common rate. A memory temporarily stores the data packets as they enter the network link, and a timer maintains a fixed time interval for releasing the data packets from the memory.

Abstract: A system and method for performing source path isolation in a network. The system comprises an intrusion detection system (IDS), a source path isolation server (SS1) and at least one router configured to operate as a source path isolation router (SR1) operating within an autonomous system. When IDS detects a malicious packet, a message is sent to SS1. SS1 in turn generates a query message (QM) containing at least a portion of the malicious packet. Then, QM is sent to participating routers located one hop away. SR1 uses the query message to determine if it has observed the malicious packet by comparing it with locally stored information about packets having passed through SR1. SR1 sends a reply to SS1, and SS1 uses the reply to identify the ingress point into the network of the malicious packet.

Abstract: A system (120) detects transmission of potentially unwanted e-mail messages. The system (120) may receive e-mail messages and generate hash values based on one or more portions of the e-mail messages. The system (120) may then determine whether the generated hash values match hash values associated with prior e-mail messages. The system (120) may determine that one of the e-mail messages is a potentially unwanted e-mail message when one or more of the generated hash values associated with the e-mail message match one or more of the hash values associated with the prior e-mail messages.

Abstract: A system (200) detects transmission of potentially malicious packets. The system (200) receives, or otherwise observes, packets and generates hash values based on variable-sized blocks of the packets. The system (200) then compares the generated hash values to hash values associated with prior packets. The system (200) determines that one of the received packets is a potentially malicious packet when one or more of the generated hash values associated with the received packet match one or more of the hash values associated with the prior packets.

Abstract: A traffic auditor (130) analyzes traffic in a communications network (100). The traffic auditor (130) performs traffic analysis on traffic in the communications network (100) and develops a model of expected traffic behavior based on the traffic analysis. The traffic auditor (130) analyzes traffic in the communications network (100) to identify a deviation from the expected traffic behavior model.