got HW crypto? On the (in)security of a Self-Encrypting Drive series Gunnar Alendal Christian Kison modg Ruhr-Universit¨at Bochum
[email protected] [email protected] [email protected] 28th September, 2015 Abstract Self encryptingdevices (SEDs) doing full disk encryptionare getting more and more widespread. Hardware implemented AES encryption provides fast and transparent encryption of all user data on the storage medium, at all times. In this paper we will look into some models in a self encryption ex- ternal hard drive series; the Western Digital My Passport series. We will describe the security model of these devices and show several security weaknesses like RAM leakage, weak key attacks and even backdoors on some of these devices, resulting in decrypted user data, without the knowledge of any user credentials. Keywords: Hardware cryptography, weak key attack, weak authentication attack, hardware RNG 1 Introduction The Western Digital My Passport and My Book devices are external hard drive series connecting to host computers using USB 2.0, USB 3.0, Thunderbolt or Firewire, depending on model. These consumer off-the-shelf hard drives are available world wide. Many of the models advertise the benefit of hardware implemented encryption. These hard drives comes pre-formatted, pre-encrypted and are supported by various free software from Western Digital, both for Windows and Mac, to manage and secure the hard disks. Setting a password to protect user-data is one important security feature. After researching the inner workings of some of the numerous models in the My Passport external hard drive series, several serious security vulnerabilities have been discovered, affecting both authentication and confidentiality of user data.