Joshua Lackey

Enhancing the security of LTE networks against jamming attacks

The long-term evolution (LTE) is the newly adopted technology to offer enhanced capacity and coverage for current mobility networks, which experience a constant traffic increase and skyrocketing bandwidth demands. This new cellular communication system, built upon a redesigned physical layer and based on an orthogonal frequency division multiple access (OFDMA) modulation, features robust performance in challenging multipath environments and substantially improves the performance of the wireless channel in terms of bits per second per Hertz (bps/Hz). Nevertheless, as all wireless systems, LTE is vulnerable to radio jamming attacks. Such threats have security implications especially in the case of next-generation emergency response communication systems based on LTE technologies. This proof of concept paper overviews a series of new effective attacks (smart jamming) that extend the range and effectiveness of basic radio jamming. Based on these new threats, a series of new potential security research directions are introduced, aiming to enhance the resiliency of LTE networks against such attacks. A spread-spectrum modulation of the main downlink broadcast channels is combined with a scrambling of the radio resource allocation of the uplink control channels and an advanced system information message encryption scheme. Despite the challenging implementation on commercial networks, which would require inclusion of these solutions in future releases of the LTE standard, the security solutions could strongly enhance the security of LTE-based national emergency response communication systems.

dHSS - distributed Peer-to-Peer implementation of the LTE HSS based on the bitcoin/namecoin architecture

The Home Subscriber Server (HSS) within the packet core of the Long Term Evolution (LTE) is a key node leveraged for essential operations, such as mutual authentication and access control. This centralized node is essential for the overall network operation as it is the cornerstone of the cryptographic functions executed in a mobile network. It stores several parameters for each subscriber, including a copy of the secret key ki that is securely stored in the Subscriber Identity Module (SIM). The advent of the Internet of Things (IoT) has sparked the concern in the industry on the potential risk of control plane signaling overloads. Due to the traffic characteristics of IoT devices and the potential risk of malfunctioning or compromised devices, there is a potential risk for floods of signaling traffic overwhelming the mobile core network and, in particular, the HSS. Moreover, recent security research has theorized potential attacks against this central core network node that could be launched from a botnet of compromised smartphones. In this paper we theoretically introduce a novel distributed and secure Peer-to-Peer (P2P) implementation of the HSS. Based on the Bitcoin/Namecoin framework, this new architecture drifts away from the symmetric key model of the standard HSS and proposes a robust public key infrastructure. Moreover, it does not rely in central points of failure, it is resilient to signaling overload threats and allows to re-authenticate and re-generate mobile session keys frequently with zero control plane signaling load at the mobile core.