摘要:
A computing device may receive content from a content source. The content may include software code that is executable by a web browser, and may be directed to another computing device. The computing device may inject security content into the content. The security content may include software instructions to enable the web browser to detect malicious software content within the content. The computing device may communicate the content to the other computing device.
摘要:
A method includes receiving a data unit, determining whether a current state, associated with a deterministic finite automata (DFA) that includes a portion of states in a bitmap and a remaining portion of states in a DFA table, is a bitmap state or not, and determining whether a value corresponding to the data unit is greater than a threshold value, when it is determined that the current state is not a bitmap state. The method further includes determining whether the current state is insensitive, when it is determined that the value corresponding to the data unit is greater than the threshold value, where insensitive means that each next state is a same state for the current state, and selecting a default state, as a next state for the current, when it is determined that the current state is insensitive.
摘要:
This disclosure describes techniques for determining whether network traffic contains one or more computer security threats. In order to determine whether a symbol stream conforms to the symbol pattern, a security device stores a full deterministic finite automaton (fDFA) that accepts streams of symbols that conform to the symbol pattern. The security device also creates a partial deterministic finite automaton (pDFA) that includes nodes that correspond to the nodes in the fDFA that have the highest visitation levels. The security device processes each symbol in the symbol stream using the pDFA until a symbol causes the pDFA to transition to a failure node or to an accepting node. If the symbol causes the pDFA to transition to the failure node, the security device processes the symbol and subsequent symbols in the symbol stream using the fDFA.
摘要:
In general, the invention is directed to techniques of identifying an infected network device in a computer network where traffic to and from the infected network device is not necessarily routed through a single point on the computer network. For example, individual line cards in network devices count incoming network flows from network devices in host tables. The host tables of all line cards of all participating network devices are then correlated. It is then determined whether the number of flows from a network device outweighs the number of flows to the network device to a significant degree. If so, the network device may be considered suspicious. Packets from a suspicious network device may be rerouted to a network security device for more thorough inspection.
摘要:
In general, techniques are described for network traffic pattern matching using adaptive deterministic finite automata (DFA). A network device may implement the techniques to promote pattern matching. The network device comprises a control unit that stores first and second data defining first and second portions of a DFA, respectively. The first data defines first states of the DFA in an uncompressed format. The second data defines second states of the DFA in a compressed format. The network device also includes an interface that receives network packets. The control unit processes the network packets to traverse the first and second states. The control unit then compares a number of times the first and second states have been traversed. Based on the comparison, the control unit dynamically reallocates the first states of the DFA in the uncompressed format and the second states of the DFA in the compressed format.
摘要:
A network security device performs a three-stage analysis of traffic to identify malicious clients. In one example, a device includes an attack detection module to, during a first stage, monitor network connections to a protected network device, during a second stage, to monitor a plurality of types of transactions for the plurality of network sessions when a parameter for the connections exceeds a connection threshold, and during a third stage, to monitor communications associated with network addresses from which transactions of the at least one of type of transactions originate when a parameter associated with the at least one type of transactions exceeds a transaction-type threshold. The device executes a programmed action with respect to at least one of the network addresses when the transactions of the at least one of the plurality of types of transactions originating from the at least one network address exceeds a client-transaction threshold.
摘要:
In general, techniques are described for reducing response times to retrieve content in an intermediate network device. In particular, the intermediate network device receives a packet from a client device of a first network that requests content from a remote network device of a second network, inspects the packet to determine whether the requested content has been previously cached to either of a first and a second memory of the device, issues a request to load the requested content from the second memory to the first memory based on the determination and queues the packet within in the queue. After queuing the packet, the intermediate network device then processes the packet to assemble a response that includes the content from the memory.
摘要:
A method includes receiving a data unit, determining whether a current state, associated with a deterministic finite automata (DFA) that includes a portion of states in a bitmap and a remaining portion of states in a DFA table, is a bitmap state or not, and determining whether a value corresponding to the data unit is greater than a threshold value, when it is determined that the current state is not a bitmap state. The method further includes determining whether the current state is insensitive, when it is determined that the value corresponding to the data unit is greater than the threshold value, where insensitive means that each next state is a same state for the current state, and selecting a default state, as a next state for the current, when it is determined that the current state is insensitive.
摘要:
In general, techniques are described for efficiently implementing application identification within network devices. In particular, a network device includes a control unit that stores data defining a group Deterministic Finite Automata (DFA) and an individual DFA. The group DFA is formed by merging non-explosive DFAs generated from corresponding non-explosive regular expressions (regexs) and fingerprint DFAs (f-DFAs) generated from signature fingerprints extracted from explosive regexs. The non-explosive regexs comprise regexs determined not to cause state explosion during generation of the group DFA, the signature fingerprints comprise segments of explosive regexs that uniquely identifies the explosive regexs, and the explosive regexs comprise regexs determined to cause state explosion during generation of the group DFA. The network device includes an interface that receives a packet and the control unit traverses first the group DFA and then, in some instances, the individual DFAs to more efficiently identify network applications to which packets correspond.
摘要:
This disclosure describes techniques for determining whether a network session originates from an automated software agent. In one example, a network device, such as a router, includes a network interface to receive packets of a network session, a bot detection module to calculate a plurality of scores for network session data based on a plurality of metrics, wherein each of the metrics corresponds to a characteristic of a network session originated by an automated software agent, to produce an aggregate score from an aggregate of the plurality of scores, and to determine that the network session is originated by an automated software agent when the aggregate score exceeds a threshold, and an attack detection module to perform a programmed response when the network session is determined to be originated by an automated software agent. Each score represents a likelihood that the network session is originated by an automated software agent.