Abstract: Systems and methods of providing secure signaling for voice communications over a public switched voice network (PSTN) are described. The call signaling is received at a first secure voice signaling gateway (SVSG) in which it is encrypted utilizing a security key. The encrypted payload is tunneled from the first SVSG to a second SVSG at a destination network element. The destination SVSG decrypts the payload and passes it on to the destination. According to the invention the communication can be either masqueraded in which the address of the first SVSG is given as the origin or non-masqueraded in which the actual original of the voice communication is retained.

Abstract: Communication network security risk exposure management systems and methods are disclosed. Risks to a communication network are determined by analyzing assets of the communication network and vulnerabilities affecting the assets. Assets may include physical assets such as equipment or logical assets such as software or data. Risk analysis may be adapted to assess risks to a particular feature of a communication network by analyzing assets of the communication network which are associated with that feature and one or more of vulnerabilities which affect the feature and vulnerabilities which affect the assets associated with the feature. A feature may be an asset itself or a function or service offered in the network and supported by particular assets, for example.

Abstract: A method and apparatus directed to detecting DoS (denial of service) attacks against SIP enabled devices. A substantial imbalance between an accounting of SIP INVITE (INV) and SIP 180 Ringing (N180) messages indicates a DoS attack. Preferably the number (H) of INVITE messages including credentials (INVc) that are sent from a user client in response to a 407 Authentication Required message from a proxy server are removed from the accounting before the balance is tested. If the equation INVo+INVc?H=N180 (where INVo is the number of INVITE messages without credentials) is not true within a small margin of error then the presence of a current DoS attack on the proxy server is indicated by the inequality.

Abstract: Systems and methods of mitigating attacks, such as Denial of Service (DoS) attacks, in a communications network are presented. Source addresses of packets received at network devices are monitored in relation to known reliable addresses stored in a decision engine. If the source address, as stored in a source table, is known as being legitimate the packets are placed in a high priority queue for transmission at the highest rate. Packets with an unknown address are placed in a lower priority queue, the source address stored in a different source table, and the packet is serviced at a lower rate. Packets that become known to be legitimate are moved from the unknown table to the table from which high priority queues are serviced. In this way, an attacker that employs spoofing techniques is prevented from overtaxing network resources.

Abstract: Methods of preventing flooding-type denial-of-service attacks in a computer-based network are described. Connection establishing messages known as SYN packets are matched with connection terminating messages (FIN packets) by using a hash algorithm. The hash algorithm or message digest uses source and destination IP addresses, port numbers, and a secret key as input parameters. The SYN packets and FIN packets are mapped to buckets using the hash algorithm and statistics are maintained for each bucket. A correspondence between SYN packets and FIN packets is maintained to close a security hole.

Abstract: A communications security system has been described. The security system in the form of a firewall is made up of a plurality of communicatively coupled sets of modules in a matrix configuration. The modules may be implemented in hardware and software in order to rely on the advantages of each technology. Data packets are typically coupled to an ingress side of the firewall where policy rules having the highest importance are checked first. The result is a high speed system having carrier class availability.

Abstract: Systems and methods of mitigating DOS attacks on a victim node in a computer based communication system are presented. According to the methods a node such as a router upstream from the victim analyzes traffic flow directed to the victim node and if a pattern indicating a possible attack is detected a notification to the effect is sent to the victim node. The victim can either ignore the notification or chose to suggest or request attack mitigation measures be implemented by the upstream router. Alternatively the upstream router can implement attack mitigation measures without waiting for input from the victim node.

Abstract: Methods of detecting TCP SYN flooding attacks at a router located between a LAN and a network such as the Internet are described. The methods rely on a counting arrangement in which SYN and Fin packets are counted on both the LAN side and the network or Internet side of the router during a time interval. Weighting factors are applied to each count, the factor for the LAN side count having the opposite polarity to the factor for the network side count. The absolute values of the sums of the weighting factors of like polarity are equal. An abnormal number of unsuccessful connection attempts are determined based on a parameter calculated using the weighting factors in conjunction with the respective counts.

Abstract: Systems and methods of mitigating attacks, such as Denial of Service (DoS) attacks, in a communications network are presented. Source addresses of packets received at network devices are monitored in relation to known reliable addresses stored in a decision engine. If the source address, as stored in a source table, is known as being legitimate the packets are placed in a high priority queue for transmission at the highest rate. Packets with an unknown address are placed in a lower priority queue, the source address stored in a different source table, and the packet is serviced at a lower rate. Packets that become known to be legitimate are moved from the unknown table to the table from which high priority queues are serviced. In this way, an attacker that employs spoofing techniques is prevented from overtaxing network resources.

Abstract: Systems and methods of mitigating attacks, such as Denial of Service (DoS) attacks, in a communications network are presented. Source addresses of packets received at network devices are monitored in relation to known reliable addresses stored in a decision engine. If the source address, as stored in a source table, is known as being legitimate the packets are placed in a high priority queue for transmission at the highest rate. Packets with an unknown address are placed in a lower priority queue, the source address stored in a different source table, and the packet is serviced at a lower rate. Packets that become known to be legitimate are moved from the unknown table to the table from which high priority queues are serviced. In this way, an attacker that employs spoofing techniques is prevented from overtaxing network resources.

Abstract: A communications security system has been described. The security system in the form of a firewall is made up of a plurality of communicatively coupled sets of modules in a matrix configuration. The modules may be implemented in hardware and software in order to rely on the advantages of each technology. Data packets are typically coupled to an ingress side of the firewall where policy rules having the highest importance are checked first. The result is a high speed system having carrier class availability.

Abstract: Methods of detecting TCP SYN flooding attacks at a router located between a LAN and a network such as the Internet are described. The methods rely on a counting arrangement in which SYN and Fin packets are counted on both the LAN side and the network or Internet side of the router during a time interval. Weighting factors are applied to each count, the factor for the LAN side count having the opposite polarity to the factor for the network side count. The absolute values of the sums of the weighting factors of like polarity are equal. An abnormal number of unsuccessful connection attempts are determined based on a parameter calculated using the weighting factors in conjunction with the respective counts.

Abstract: Methods of preventing flooding-type denial-of-service attacks in a computer-based network are described. Connection establishing messages known as SYN packets are matched with connection terminating messages (FIN packets) by using a hash algorithm. The hash algorithm or message digest uses source and destination IP addresses, port numbers, and a secret key as input parameters. The SYN packets and FIN packets are mapped to buckets using the hash algorithm and statistics are maintained for each bucket. A correspondence between SYN packets and FIN packets is maintained to close a security hole.