Chapter 4. Secure Design of IoT Devices

A 2017 survey by the MPI Group found that just 47% of IoT manufacturers consider security during the conceptualization or design stage. Only 21% begin thinking about security during production, and 18% wait until the Quality Assurance (QA) phase. The remainder don't consider security until the marketing phase of their product.

Read the full survey results at the following link: https://www.bdo.com/getattachment/9adeb668-5c54-47b7-9108-08ad37fe6fd3/attachment.aspx.

This data backs up what we have already seen in the news. The proliferation of Mirai and other botnets has been aided by products that have failed to incorporate even minimum security controls. Yet, introducing security from the start of a project is difficult. Developers must overcome challenges in fielding secure products and systems.

This chapter discusses secure design approaches for IoT systems. We will address:

• Challenges that developers face in securing IoT systems
• Design goals for secure...

The challenge of secure IoT development

We focus here on the concept of IoT systems. This includes not only the integration of multiple IoT products and supporting services for an organization, but also discrete IoT products sold by developers.

Rarely does an IoT product developer bring a single device to market. Instead, offerings include interfaces for mobile applications, cloud services, peer devices, and data services. Often, the IoT product developer maintains the device during operation (such as through a subscription service).

We therefore consider an IoT product itself as a component in a larger system or systems. Product developers should begin adopting a system engineering mindset to understand the risks associated with interactions between multiple components within a system. 

IoT developers must meet market demands, stay up to date with fast-changing technology, keep their products secure, and remain competitive on cost. This is not easy, even for organizations that have extensive...

Secure design goals

There is no one-size-fits-all secure design for an IoT (or any other) system. Some IT systems operate in a threat environment that requires them to operate offline and air-gapped from any other network. Even these systems face novel attack methods, such as social engineering and insider threats.

No system is ever 100% secure; however, we can define goals for a secure, available, and resilient system that reliably mitigates attacks from all but the most determined adversaries.

Here we define some of these goals, and describe ways to achieve them within your IoT systems. Tailor each of these as necessary to fit your unique system requirements and threat profile.

Design IoT systems that mitigate automated attack risks

If you examine some of the major botnet variants from the last few years, you'll notice that their success is driven primarily based on the lack of good cyber hygiene applied to IoT devices.

Bashlight, for example, compromised more than a million IoT devices by...

Summary

This chapter discussed some of the challenges that IoT system developers face when trying to secure their systems, and detailed a set of secure design goals for IoT systems.

We discussed methods for designing IoT systems to mitigate automated attack risks, securing points of integration, implementing hardware protection measures, and building resilient systems.

In Chapter 5, Operational Security Life Cycle, we will explore a secure operational life cycle for IoT systems.