Signaling attacks in mobile telephony

Mobile telephony based on UMTS uses finite-state control schemes for wireless channels and for signaling across the network. These schemes are used systematically in various phases of the communication and are vulnerable to attacks that can bring down the network through unjustified bandwidth allocation and excessive signaling across the control plane. In this paper we identify those system parameters which are critical to the success of such attacks, and propose changes that can limit the effect of the attack. The approach is based on establishing a mathematical model of a UMTS system that is undergoing attacks, and on showing how parameters can be optimally modified to minimise the effect of the attack as experienced by the mobile device and the network.