Attacks against IoT systems are increasing at an alarming pace. Many IoT systems are and will be built using low-cost micro-controllers (IoT-uCs). Different security mechanisms have been proposed for IoT-uCs with different trade-offs. To guarantee a realistic and practical evaluation, the constrained resources of IoT-uCs require that defenses must be evaluated with respect to not only security, but performance, memory, and energy as well. Evaluating security mechanisms for IoT-uCs is limited by the lack of realistic benchmarks and evaluation frameworks. This burdens researchers with the task of developing not only the proposed defenses but applications on which to evaluate them. As a result, security evaluation for IoT-uCs is limited and ad-hoc. A sound benchmarking suite is essential to enable robust and comparable evaluations of security techniques on IoT-uCs. This paper introduces BenchIoT, a benchmark suite and evaluation framework to address pressing challenges and limitations for evaluating IoT-uCs security. The evaluation framework enables automatic evaluation of 14 metrics covering security, performance, memory usage, and energy consumption. The BenchIoT benchmarks provide a curated set of five real-world IoT applications that cover both IoT-uCs with and without an OS. We demonstrate BenchIoT's ability by evaluating three defense mechanisms. All benchmarks and the evaluation framework is open sourced and available to the research community.

Embedded systems are ubiquitous in every aspect of modern life. As the Internet of Thing expands, our dependence on these systems increases. Many of these interconnected systems are and will be low cost bare-metal systems, executing without an operating system. Bare-metal systems rarely employ any security protection mechanisms and their development assumptions (unrestricted access to all memory and instructions), and constraints(runtime, energy, and memory) makes applying protections challenging. To address these challenges we present EPOXY, an LLVM-based embedded compiler. We apply a novel technique, called privilege overlaying, wherein operations requiring privileged execution are identified and only these operations execute in privileged mode. This provides the foundation on which code-integrity, adapted control-flow hijacking defenses, and protections for sensitive IO are applied. We also design fine-grained randomization schemes, that work within the constraints of bare-metal systems to provide further protection against control-flow and data corruption attacks. These defenses prevent code injection attacks and ROP attacks from scaling across large sets of devices. We evaluate the performance of our combined defense mechanisms for a suite of 75 benchmarks and 3 real-world IoT applications. Our results for the application case studies show that EPOXY has, on average, a 1.8% increase in execution time and a 0.5% increase in energy usage.