Abstract: A session table includes one or more records, where each record represents a session. Session record information is stored in various fields, such as key fields, value fields, and timestamp fields. Session information is described as keys and values in order to support query/lookup operations. A session table is associated with a filter, which describes a set of keys that can be used for records in that table. A session table is populated using data contained in security information/events. Rules are created to identify events related to session information, extract the session information, and use the session information to modify a session table. A session table is partitioned so that the number of records in each session table partition is decreased. A session table is processed periodically so that active sessions are moved to the current partition.

Abstract: A unique identifier is assigned to a network node and is used to obtain an “asset model” corresponding to the node and to determine whether the node is a member of a particular category. An asset model is a set of information about a node (e.g., the node's role within the enterprise, software installed on the node, and known vulnerabilities/weaknesses of the node). An identifier lookup module determines a node's identifier based on characteristics of the node (such as IP address, host name, network zone, and/or MAC address), which are used as keys into lookup data structures. A category lookup module determines whether a particular node is a member of (i.e., within) a particular category using a transitive closure to model the categories (properties) that can be attached to an asset model. A transitive closure for a particular asset category is stored as a bitmap, similar to bitmap indexing.

Abstract: A prefix expression tree showing an expression can be supplemented to also display the expression in infix notation. In one embodiment, the present invention includes displaying an expression being capable of representation in infix and prefix notation in prefix expression tree format. In one embodiment, the expression includes a plurality of operators and operands, and the plurality of operands make up the leaves of the expression tree. In one embodiment, the present invention further includes inserting a plurality of infix operators corresponding with the plurality of operators into the prefix expression tree, wherein, the plurality of operands and infix operators represent the expression in infix notation.

Abstract: A network security system is provided that receives information from various sensors and can analyse the received information. In one embodiment of the present invention, such a system receives a security event from a software agent. The received security event includes a target address and an event signature, as generated by the software agent. The event signature can be used to determine a set of vulnerabilities exploited by the received security event, and the target address can be used to identify a target asset within the network. By accessing a model of the target asset, a set of vulnerabilities exposed by the target asset can be retrieved. Then, a threat can be detected by comparing the set of vulnerabilities exploited by the security event to the set of vulnerabilities exposed by the target asset.

Abstract: In one embodiment, the present invention provides for receiving security events from a network device by a distributed software agent of a network security system, determining a priority of each received security event, and storing the security events in a plurality of prioritized event buffers based on the determined priorities for a period of time determined by a timer. Upon expiration of the timer, a batch of security events for transport to a security event manager of the network security system can be created by including security events in the batch in order of priority until the batch is full.