LTE (Long Term Evolution) is the latest cellular communications standard to provide advanced mobile services that go beyond traditional voice and short messaging traffic. Mobility networks are experiencing a drastic evolution with the advent of Machine to Machine (M2M) systems and the Internet of Things (IoT), which is expected to result in billions of connected devices in the near future. In parallel, the security threat landscape against communication networks has rapidly evolved over the last few years, with major Distributed Denial of Service (DDoS) attacks and the substantial spread of mobile malware. In this paper we introduce Firecycle, a new modeling and simulation platform for next-generation LTE mobility network security research. This standards compliant platform is suitable for large-scale security analysis of threats against a real LTE mobile network. It is designed with the ability to be distributed over the cloud, with an arbitrary number of virtual machines running different portions of the network, thus allowing simulation and testing of a full-scale LTE mobility network with millions of connected devices. Moreover, the mobile traffic generated by the platform is modeled from real data traffic observations from one of the major tier-1 operators in the US.