Random Access Failure Attack on Cellular Networks: Forcing Timing Advance Misalignment

Cellular networks such as 4G and 5G have been exceedingly successful, but have encountered a parallel surge in security threats. Random access (RA) is an essential procedure performed between a user and a base station to facilitate attachment to the network and obtaining radio resources for downlink and uplink transmissions. Particularly, users get tightly synchronized to the base station based on the timing advance (TA) command that estimates propagation delay over the air during the RA procedure. In this paper, we investigate security issues related to the transmission and reception of TA information, and scheduled uplink transmission during the RA procedure in cellular networks. Furthermore, we present a random access failure attack that forces TA misalignment to users and thus results in service failure of legitimate users in the network. Finally, we verify our analysis through software-defined radio (SDR) based experiments.