Securing the Next Steps in Signaling (NSIS) Protocol Suite

The Next Steps in Signaling (NSIS) protocol suite represents an extensible framework for enabling various signaling applications over IP-based networks. The framework consists of two layers that need different types of security protection: the lower layer mainly deals with the discovery of adjacent peers, establishment of channel security to protect the delivery of signaling messages between two peers, while the upper layer provides the signaling application specific functionalities. Different security properties are desired at the two layers with stronger authorization functionality at the signaling application layer. In this paper we examine how various security vulnerabilities can be utilized by an adversary, including eavesdropping, man-in-the-middle attacks, fraud and denial of service attacks. Moreover, we describe how to protect against a number of selected security threats and highlight some security challenges that require further research.