The (In)Security of Automotive Remote Keyless Entry Systems (revisited),

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Presented at Ruhrsec 2017 by

David Oswald

Remote keyless entry (RKE) systems, usually based on so-called rolling codes, are the most widespread way of (un)locking vehicle doors, opening the trunk, and disarming the alarm system. RKE is based on the unidirectional transmission of an (increasing) counter value, authenticated by means of symmetric cryptography. There are two major ways of attacking RKE systems: (i) by exploiting vulnerable key distribution schemes, and (ii) by making use of cryptographical weaknesses in the employed ciphers. In this talk, we will give practical example for both cases (based on our Usenix Security 2016 paper). First, we show that the RKE system used by the VW group (Audi, Seat, Skoda, Volkswagen) was based on only a handful global keys over the past 20 years. By extracting these keys from ECU firmware, an adversary is able to clone the owner's remote control from a distance of up to 100m, using a single rolling code. Second, we present novel attacks on the Hitag2 RKE scheme (employed by Alfa Romeo, Peugeot, Lancia, Opel, Renault, and Ford among others). Based on black-box reverse-engineering of the protocol, we devise a new cryptanalytical attack on Hitag2 for full key recovery, requiring four to eight rolling codes and negligible computation. Finally, our talk also includes a brief survey of the state of automotive security in general, a discussion of the responsible disclosure process, and recommendations for designing more secure RKE systems.