TRUSTED BUILDING BLOCKS FOR RESILIENT EMBEDDED SYSTEMS DESIGN

Abstract

The use of small embedded and IoT devices have increased monumentally with technological advancements and industry 4.0 evolution. These devices are widely used in applications ranging from home security systems, sensors network, smart appliances, industrial control systems, and Electronic Control Units (ECU)'s in cars. They are used to collect, process, and transfer security-critical user information and data. Attackers can leak, steal, modify and misuse their security critical information in malicious activities. Thus, the security and assurance that the device runs untempered, vendor authorized trusted code becomes an open security problem. Secure boot and remote attestation (RA) are widely used security primitives that verifies the integrity and authenticity of the software code running on the devices at boot-time and periodic runtime, respectively. TPM2.0 and trust-zone based complex hybrid solutions provides different categories of attacks detection and prevention with the use of access control and encryption. Other techniques such as control flow and data flow attestation are widely used for detecting malicious code execution during runtime. Secure-boot and RA focuses on the detection of malicious code presents and leaves the device un-operational state. They relies on manual or over-the-air or code re-flash to bring the device back to the operational state. The resilience of the embedded device is defined as, its ability to detect the presence of different types of attacks, prevent them from being executed and provide the recovery techniques to bring the device back to the normal operational state. Smart attacks can corrupt the networking stack to disable over the air code re-flashing and due to placing of the devices in industrial control plants, ECU's, smart cameras , manual code reflash sometimes becomes not viable solution. The resilient small embedded system design needs attacks detection, prevention and recovery at both boot-time and continues runtime.Therefore, this dissertations outlines several solutions for augmenting attack resiliency in small embedded and IOT devices. The techniques can be easily adapted to existing systems as they requires very little or no hardware overhead. The dissertations first implements TPM2.0 based end-to-end device attestation technique with TLV format of the event logs. It than showcases two different implementation of lightweight attack detection, prevention and onboard recovery techniques. lastly, it presents lightweight novel control register based continuous runtime resilience techniques. The hybrid solutions have been implemented and tested on the FPGA for Proof Of Concept (POC) validation. The results of the state-of-the-art comparison and evaluation are presented. Furthermore, to demonstrate that the proposed solution adheres the security and specifications, a novel end-to-end formal verification framework is proposed to gain the confidence in the system design. Thus, these dissertations paves the way for attack resilient embedded systems design and provides explores the future research direction.