The firmware of any processor, programmable logic controller (PLC), Remote Terminal Unit (RTU), routers and other Industrial IoT devices are pieces of low-level software that are responsible for booting the device to implementing various functions that employ simpler instructions to implement functions in lieu of more complex instructions. The firmware is also the mechanism through which security patches are made to devices when a hardware level vulnerability is discovered. As a result, security of firmware is very important from various threat possibilities – for example, secure boot of the device, authenticity of firmware patches, vulnerabilities of software – such as buffer overflow, and the certification of the authenticity of firmware. It turns out that in many well-known attacks, firmware update with falsified digital certificates purportedly from the original developer of the firmware played a significant role in the attack (e.g. STUXNET). Also, to boot-strap trust in a system that is otherwise untrusted, a trusted computing base (TCB) is implemented in modern devices. The trusted base is implemented in hardware and firmware combination, and all trusted computing in other layers derive the trust by the security of the TCB implementation. Another threat of work in this layer is cryptography, multi-party computation, and cryptographic protocols for security and trust.
Some of the major issues at this layer are:
i. Secure Boot methods and Proving Security Properties of Secure boot
ii. Firmware and firmware patch trustworthiness and authenticity
iii. Vulnerability discovery of firmware
iv. Vulnerability of Enclave architectures and other TCB architecture v. Cryptography, Multi-Party Computation, and Light-weight Cryptography