CVE-2017-3226 — Generation of Predictable IV with CBC Mode in U-boot

Das U-Boot is a device bootloader that can read its configuration from an AES encrypted file. Devices that make use of Das U-Boot's AES-CBC encryption feature using environment encryption (i.e., setting the configuration parameter CONFIG_ENV_AES=y) read environment variables from disk as the encrypted disk image is processed. An attacker with physical access to the device can manipulate the encrypted environment data to include a crafted two-byte sequence which triggers an error in environment v…