⚙️ Operating Systems19 min
Securing Embedded Linux Devices: IoT Firmware Hardening Guide
A
Muhammad Asim Chattha
Software Developer & Cybersecurity Researcher
#Embedded Linux#IoT#Firmware#Secure Boot#Yocto
Embedded Linux powers billions of IoT devices — many of which ship with woefully inadequate security. This guide covers practical hardening.
Hardening Checklist
- **Secure Boot Chain**: U-Boot verified boot → signed FIT images → dm-verity for rootfs integrity
- **Filesystem Encryption**: dm-crypt/LUKS2 for data-at-rest protection on eMMC/SD
- **Mandatory Access Control**: SELinux policies for process isolation and least privilege
- **Read-Only Rootfs**: OverlayFS for runtime writes with factory reset capability
- **Runtime Integrity**: IMA/EVM for file integrity measurement and appraisal
- **Update Mechanism**: A/B update scheme with rollback protection and signed OTA artifacts