Embedded System Security
Embedded system security encompasses the principles, techniques, and tools used to protect purpose-built computing systems — including microcontrollers, real-time operating systems, and their software — from exploitation, tampering, and unauthorised access.
Embedded systems are specialised computers designed to perform dedicated functions within larger devices or products. Unlike general-purpose computers, they typically run bare-metal code or real-time operating systems (RTOS) such as FreeRTOS, Zephyr, or VxWorks. They are found in everything from smart home appliances and medical devices to automotive ECUs and industrial PLCs. Securing these systems presents unique challenges due to resource constraints, long deployment lifecycles, and limited update capabilities.
Common security issues in embedded systems include the use of hardcoded credentials for debug or administrative access, unprotected communication interfaces (UART, SPI, I2C, JTAG), outdated operating systems and libraries that no longer receive security patches, lack of secure boot mechanisms allowing firmware tampering, and insufficient input validation that leads to buffer overflows in C/C++ codebases.
A comprehensive embedded security strategy starts at the design phase with threat modelling specific to the device's deployment environment and attack surface. Secure coding practices must account for the constraints of embedded environments — limited memory means traditional security libraries may not fit, and real-time requirements mean security operations cannot introduce unpredictable latency.
Key defensive measures include implementing secure boot chains that verify firmware integrity at every stage, using hardware-backed key storage via TPMs or secure elements, enforcing memory protection units (MPUs) to isolate critical code, stripping debug interfaces from production builds, and establishing a vulnerability disclosure and patching programme that accounts for the full product lifecycle.