Electric Vehicles Vulnerable to Attack that Prevents Charging

Researchers Richard Baker and Sebastian Köhler (with Ivan Martinovic) from the Department of Computer Science at the University of Oxford, and Martin Strohmeier of armasuisse Science + Technology, have discovered a cyber attack that causes electric vehicles to stop charging. It can be conducted wirelessly from significant distance and allows individual vehicles to be disrupted in a stealthy way, or even entire fleets to be denied charging en masse.

It has been dubbed the Brokenwire attack by the authors. The attack causes communication to fail between the vehicle and charger, with the result that an error state is triggered and the charging session aborted. This can either be used to prevent the initiation of a charging session, or interrupt one at any point during power delivery. During testing, the researchers were able to disrupt a real charging session from up to 47 metres away, as well as conducting ‘drive-by’ attacks, interrupting charging on different floors of a building and disrupting charging for multiple vehicles at once. Seven vehicles and 18 chargers were tested and all found to be vulnerable. None of the vehicles restarted the charging automatically after the attack – all had to be manually unplugged and reconnected to start charging again. Even then, the attack must cease for a new session to start successfully, otherwise further connections will also be terminated. However, no permanent damage is dealt to either the vehicle or charger.

The Brokenwire attack affects direct-current fast-chargers using the Combined Charging System (CCS). This includes all plugs marked as ‘CCS’ in public-facing chargers, along with any compliant implementation of the ISO 15118 and DIN 70121 standards (with the exception of implementations using solely ISO 15118-8 wireless communication). Other charging technologies (CHAdeMO, GB/T, Supercharger) are not affected. Given the prominence of CCS as a charging standard, the authors believe this attack to represent a threat to a substantial proportion of the approximately 12M battery EVs owned worldwide.1 The affected DC chargers are only one, increasingly important, part of the charging infrastructure for personal cars – but are critical for high-usage fleets such as buses, HGVs and taxis that depend on frequent, fast recharging. Moreover, CCS is also poised to play a decisive role in the future of the power grid by enabling bi-directional charging, intertwining EVs even further into critical infrastructure2.

Industry and government bodies have been informed and are working to fix the vulnerability. To support this, technical details on how to conduct the attack have been redacted from public materials. However, comprehensive details of the evaluation and evidence of the impact are openly available. Further information on Brokenwire is available at https://www.brokenwire.fail