Relay Attacks on Secure Element-enabled Mobile Devices: Virtual Pickpocketing Revisited

Near Field Communication's card emulation mode is a way to combine smartcards with a mobile phone. Relay attack scenarios are well-known for contactless smartcards. In the past, relay attacks have only been considered for the case, where an attacker has physical proximity to an NFC-enabled mobile phone. However, a mobile phone introduces a significantly different threat vector. A mobile phone's permanent connectivity to a global network and the possibility to install arbitrary applications permit a significantly improved relay scenario. This paper presents a relay attack scenario where the attacker no longer needs physical proximity to the phone. Instead, simple relay software needs to be distributed to victims' mobile devices. This publication describes this relay attack scenario in detail and assesses its feasibility based on measurement results.