Investigations in intercepting the physical layer of GSM: Enabling advanced impact-assessments in terms of security and reliability

Since its final specification in the year 1990, the Global System for Mobile Communications (GSM) has been promoted to one of the most used baseline standards when it comes to mobile communication. Being a generation of a technology that has currently reached its 4
^th
generation (Long Term Evolution, short: LTE), GSM seems to be deprecated. Showing this assumption untrue, GSM is often selected as a “fallback” technology assumed to be applicable in almost every cell phone-enabled region, denying the potential risks in security and reliability which is inherent in mature technologies. This paper presents current research results in utilising Software Defined Radio (SDR) technology intercepting the physical communications layer of GSM (UM-interface), to enable further research in the verification and documentation of known and novel security breaches.