A Hybrid, Stateful and Cross-Protocol Intrusion Detection System for Converged Applications

Abstract

Although sharing the same physical infrastructure with data networks makes convergence attractive, it also makes Voice over Internet Protocol (VoIP) networks and applications inherit all the security weaknesses of IP protocol. In addition, VoIP converged networks come with their own set of security concerns. Voice traffic on converged networks is packet switched and vulnerable to interception with the same techniques used to sniff other traffic on a LAN or WAN. Denial of Service (DoS) attacks are one of the most critical threats to VoIP due to the disruption of service and loss of revenue they cause. VoIP systems are supposed to provide the same level of security provided by traditional PSTN networks, although more functionality and intelligence are distributed to the endpoints, and more protocols are involved to provide better service. All these factors make a new design and techniques in Intrusion Detection highly needed. In this paper we propose a novel host based intrusion detection architecture for converged VoIP applications. Our architecture uses the Communicating Extended Finite State Machines formal model to provide both stateful and cross-protocol detection. In addition, it combines signature-based and specification-based detection techniques alongside combining protocol syntax and semantics anomaly detection. A variety of attacks are implemented on our test bed, and the intrusion detection prototype shows promising efficiency. The accuracy of the prototype detection is discussed and analyzed.