Abstract: Recently, Denial of Service(DoS) attacks and Distributed DoS(DDoS) attacks which are stronger form of DoS attacks from plural hosts have become security threats on the Internet. It is important to identify the attack source and to block attack traffic as one of the measures against these attacks. In general, it is difficult to identify them because information about the attack source is falsified. Therefore a method of identifying the attack source by tracing the route of the attack traffic is necessary. A traceback method which uses traffic patterns, using changes in the number of packets over time as criteria for the attack traceback has been proposed. The traceback method using the traffic patterns can trace the attack by matching the shapes of input traffic patterns and the shape of output traffic pattern observed at a network branch point such as a router. The traffic pattern is a shapes of traffic and unfalsifiable information. The proposed trace methods proposed till date cannot obtain enough tracing accuracy, because they directly use traffic patterns which are influenced by non-attack traffics. In this paper, a new traffic pattern matching method using Independent Component Analysis(ICA) is proposed.
Abstract: A person-to-person information sharing is easily realized
by P2P networks in which servers are not essential. Leakage
of information, which are caused by malicious accesses for P2P
networks, has become a new social issues. To prevent information
leakage, it is necessary to detect and block traffics of P2P software.
Since some P2P softwares can spoof port numbers, it is difficult to
detect the traffics sent from P2P softwares by using port numbers.
It is more difficult to devise effective countermeasures for detecting
the software because their protocol are not public.
In this paper, a discriminating method of network applications
based on communication characteristics of application messages
without port numbers is proposed. The proposed method is based
on an assumption that there can be some rules about time intervals
to transmit messages in application layer and the number of necessary
packets to send one message. By extracting the rule from network
traffic, the proposed method can discriminate applications without
port numbers.