What to Protect: MCU Security

This post is going to focus on some particular security issues in the embedded space (the IoT space, if you will). I regularly work with microcontrollers (MCUs) based on variants of the Cortex-M architecture. These are ARM processors that typically have a small amount of ROM (½–1 MiB) and an even smaller amount of RAM (16–128 KiB). Traditionally, security has not been much of a focus on these types of devices (think toasters, washing machines, and the likes).