Automated runtime risk management for voice over IP networks and services

Voice over IP (VoIP) has become a major paradigm for providing telephony services at a lower cost and with a higher flexibility. VoIP infrastructures are however exposed to multiple security issues both inherited from the IP layer and specific to the application layer. In the meantime, protection mechanisms are available but may seriously impact on the continuity and quality of such critical services. We propose in this paper an automated risk management schema for continuously adapting VoIP equipment exposure by activating security safeguards in a dynamic and progressive manner. We describe the architecture supporting our solution, the considered risk model taking into account VoIP properties and the algorithms for restricting and relaxing the risk level of the VoIP service at runtime. The benefits and limits of our solution are evaluated through an implementation prototype and an extensive set of experimental results in the case scenario of SPIT attacks.