HCI

This post refutes the claim that researchers found a “backdoor” in ESP32 Bluetooth chips. What the researchers highlight (vendor-specific HCI commands to read & write Controller memory) is a common design pattern found in other Bluetooth chips from other vendors as well, such as Broadcom, Cypress, and Texas Instruments. Vendor-specific commands in Bluetooth effectively constitute a “private API”, and a company’s choice to not publicly document their private API does not constitute a “backdoor”.

4 day class covering the full Bluetooth Low Energy (BLE) protocol stack from the bottom (PHY) up to the top (GATT). The core of the class is built around playing with a game application on an Android phone, talking via Bluetooth to an IoT-type piece of hardware, and analyzing the communication between them. The 4th day is focused on assessing a cutomized Ultra-Vulnerable Peripheral firmware, running on Zephyr RTOS, which has had vulnerabilities introduced into it which are representative of vulnerabilities found in the past across many other platforms.