Questioning the feasibility of UMTS-GSM interworking attacks

Recently, Ahmadian et al. (Security enhancements against UMTS-GSM interworking attacks, Elsevier, Amsterdam, 2010) presented and analyzed three different attacks that can be performed in UMTS-GSM interworking networks: (a) a real-time eavesdropping attack, (b) an offline eavesdropping attack, and (c) an impersonation attack. In this letter we question the feasibility of these attacks. In particular, we pinpoint and analyze that these attacks are based on some erroneous and misleading assumptions that the authors have made regarding the security functionality of the UMTS-GSM interworking networks. Based on this analysis, we deduce that these three attacks cannot be performed. © 2011 Springer Science+Business Media, LLC