Secure firmware validation and update for consumer devices in home networking

Embedded systems are more than ever present in consumer electronics devices such as home routers, personal computers, smartphones, smartcards, various sensors to name a few. Firmware, which is embedded software specifically designed for monitoring and control in resource constrained conditions, was not a major attack target. However, recent serious cyber attacks focus on firmware rather than application or operating system levels, because exploiting the firmware level offers stealth capabilities, e.g., anti-virus software and operating system cannot reveal such a firmware level exploit. A firmware validation that ensures firmware integrity is thus required to detect firmware tempering attacks. A remote firmware update is also required for consumer devices connected to the Internet. In this paper, a secure firmware validation and update scheme is introduced for consumer devices in a home networking environment. The proposed scheme utilizes an IDbased mutual authentication and key derivation to securely distribute a firmware image. A firmware fragmentation with hash chaining is also applied to guarantee authenticity of the fragmented firmware image. Security analysis results are presented while considerations are discussed.