Smart PRACH Jamming: A Serious Threat for 5G Campus Networks

Smart jamming attacks on cellular campus networks represent an enormous potential threat, especially in the industrial environment. In complex production processes, the disruption of a single wireless connected Cyber-Physical System (CPS) is enough to cause a large-scale failure. In this paper, a smart jamming attack on the Physical Random Access Channel (PRACH) of a 5G system is modeled. This is followed by a practical implementation of the jammer on a testbed based on Open Air Interface (OAI) and Software Defined Radios (SDRs). It is shown that the designed jammer design can interfere a legitimate transmission of a PRACH preamble with a ratio of more than 99.9%. While less than one percent of the cell resources are interfered compared to broadband jamming. In addition, two different types of jamming signal spectra are compared in relation to their interference capacity. The developed attack can be re-implemented based on publicly available source code and Commercial Off-The-Shelf (COTS) hardware.