A New Zero-Trust Model for Securing Embedded Systems

Credits: Embedded World Conference 2019 Proceedings, http://www.embedded-world.eu

Abstract — The attack surface in embedded systems has grown exponentially as connectivity requirements are increasingly met with the integration of readily available 3rd party libraries. A new Zero Trust Model is required to address the intrinsic security threat posed by the resulting monolithic firmware. This paper explores a new modern approach based on open source hardware and software where security through separation is achieved via a state-of-the-art multi-domain Trusted Execution Environment (TEE) for RISC-V processors.

INTRODUCTION
Embedded devices are a part of the daily lives of people all around the world. As devices get more personal and become placed in increasingly sensitive environments, the security of those devices becomes paramount. Security is a multi-tier approach, with different solutions being used across the industry depending on device capabilities and functionalities. Most security challenges faced by those resource-constrained devices that make up the Internet of Things can be minimized by enforcing physical separation between functional blocks and by properly implementing established encryption schemas to protect data in transit and at rest.

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Trusted Execution Environments – A System Design Perspective

Credits: Embedded World Conference 2019 Proceedings, http://www.embedded-world.eu

Abstract — The Internet of Things (IoT) represents a collection of billions of smart, connected devices. Current approaches to securing IoT devices typically go through the addition of complex hardware mechanisms or the implementation of heavy containerization and virtualization solutions. In this paper, we take the reader through designing a real-world scenario of an IoT device making use of Trusted Execution Environments (TEE) to securely isolate different parts of the system. We aim to demonstrate a network connected device resembling a typical IoT device with a clear boundary separation between the application, the networking stack, and the root of trust.

INTRODUCTION
The Internet of Things (IoT) field has proliferated, with current estimates at 11 billion devices according to a recent Development Bank of Singapore (DBS) report [13]. According to the same report, privacy, security, and interoperability are the key barriers for widespread adoption [11]. While attempts at interoperability and standardization exist with organizations such as EdgeX [9], privacy and security still remain largely unaddressed. IoT devices do not work in isolation, they typically need to communicate with a central manager, posting their results and accepting commands from that central manager. Typical forms of communication involve protocols like BLE and TCP/IP. These protocols bring complex serializers and de-serializers often vulnerable to buffer overflow exploits, use after free and so on, with the latest examples being vulnerable TCP/IP stacks that could be exploited [12].

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How to Secure a RISC-V Embedded System in Just 30 Minutes

Credits: Embedded World Conference 2019 Proceedings, http://www.embedded-world.eu

Abstract — The free and open RISC-V ISA defines many important building blocks of security. Properly implementing them is the system designer responsibility. So, the real question is: How does one properly secure a RISC-V embedded system? This paper offers a practical guide to using these security blocks to build a state-of-the-art Trusted Execution Environment (TEE) with a multitude of isolated security domains – Zones, and secure communications between them. The paper also shows how to verify Zone isolation and benchmark overall TEE system performance.

INTRODUCTION
Originally developed at U.C. Berkeley, the free and open RISC-V ISA promises to bring the innovation and collaboration of the open source community to the hardware world. When it comes to security, RISC-V specifications [1] provide many important building blocks and the rapidly growing RISC-V ecosystem even more. For designers used to traditional closed-source proprietary architectures, the complexity associated with properly implementing these new security technologies may prove daunting [2].

From a system design perspective, the real question is: How do I properly secure a RISC-V embedded system? In this paper, we describe how to secure a RISC-V system using the free and open MultiZone Security Trusted Execution Environment (TEE) – developed and maintained by Hex Five Security, Inc. MultiZone Security provides signed boot, hardware enforced isolation for an unlimited number of security domains – Zones, a secure messaging system between Zones, secure interrupts, and operates on top of the standard RISC-V ISA.

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