This blogpost explains how we recovered the firmware of a fleet-sharing Electronic Control Unit (ECU) which has been erased from a FAT memory using Capstone disassembler to locate scattered parts, to be able to reverse-engineer it.

An overview of the TrustZone was given in a previous article. This second article more technically addresses the attack surface and hotspots exposed to an attacker, as well as what can be done once code execution is achieved in the different privilege levels available in TrustZone.

Increasing popularity of connected devices in recent years has led devices manufacturers to deal with security issues in a more serious way than before. In order to address these issues appropriately, a specification has emerged to define a way to ensure the integrity and confidentiality of data running in the entity implementing this specification.