Specify security requirements for IoT workloads

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The Internet of Things (IoT) supports billions of connected devices that use operational technology (OT) networks. IoT/OT devices and networks are often designed without security in priority, and therefore can't be protected by traditional systems. With each new wave of innovation, the risk to IoT devices and OT networks increases the possible attack surfaces.

Securing an Internet of Things (IoT) infrastructure requires a rigorous security-in-depth strategy. This strategy requires you to secure data in the cloud, protect data integrity while in transit over the public internet, and securely provision devices. Each layer builds greater security assurance in the overall infrastructure.

This security-in-depth strategy can be developed and executed with active participation of various players involved with the manufacturing, development, and deployment of IoT devices and infrastructure. Here is a high-level description of these roles and security requirements:

Role Role Description Security Requirements
IoT hardware manufacturer/integrator Typically, these players are the manufacturers of IoT hardware being deployed, integrators assembling hardware from various manufacturers, or suppliers providing hardware for an IoT deployment manufactured or integrated by other suppliers. Scope hardware to minimum requirements:
Make hardware tamper proof
Make hardware tamper proof
Make upgrades secure
IoT solution developer The development of an IoT solution is typically done by a solution developer. This developer may part of an in-house team or a system integrator (SI) specializing in this activity. The IoT solution developer can develop various components of the IoT solution from scratch or integrate various off-the-shelf or open-source components. Follow secure software development methodology
Choose open-source software with care
Integrate to avoid security flows
IoT solution deployer After an IoT solution is developed, it needs to be deployed in the field. This process involves deployment of hardware, interconnection of devices, and deployment of solutions in hardware devices or the cloud. Deploy hardware securely
Keep authentication keys safe
IoT solution operator After the IoT solution is deployed, it requires long-term operations, monitoring, upgrades, and maintenance. These tasks can be done by an in-house team that comprises information technology specialists, hardware operations and maintenance teams, and domain specialists who monitor the correct behavior of overall IoT infrastructure. Keep the system up-to-date
Protect against malicious activity
Audit frequently
Audit frequently
Protect cloud credentials

Connected special-purpose devices have a significant number of potential interaction surface areas and interaction patterns, all of which must be considered to provide a framework for securing digital access to those devices. The term "digital access" is used here to distinguish from any operations that are carried out through direct device interaction where access security is provided through physical access control. For example, putting the device into a room with a lock on the door. While physical access can't be denied using software and hardware, measures can be taken to prevent physical access from leading to system interference.

As you explore the interaction patterns, look at "device control" and "device data" with the same level of attention. "Device control" can be classified as any information that is provided to a device by any party with the goal of changing or influencing its behavior towards its state or the state of its environment. "Device data" can be classified as any information that a device emits to any other party about its state and the observed state of its environment.

In order to optimize security best practices, it's recommended that a typical IoT architecture is divided into several component/zones as part of the threat modeling exercise. These zones are:

  • Device

  • Field Gateway

  • Cloud gateways

  • Services

Zones are a broad way to segment a solution; each zone often has its own data and authentication and authorization requirements. Zones can also be used to isolation damage and restrict the impact of low trust zones on higher trust zones. Each zone is separated by a Trust Boundary, and it represents a transition of data/information from one source to another. During this transition, the data/information could be subject to Spoofing, Tampering, Repudiation, Information Disclosure, Denial of Service and Elevation of Privilege (STRIDE).

Security posture management and threat detection

Just like any other cloud workload, IoT workloads need to have an ongoing security assessment to improve the overall security posture. In addition, you need threat detection in place to better understand current attack vectors and how to respond. An important part of the security requirements for IoT is to adopt a solution that can provide both: security posture management and threat detection.

Microsoft Defender for IoT is a unified security solution for identifying IoT devices, vulnerabilities, and threats and managing them through a central interface.

Diagram that shows unified posture management in Defender for I o T.

Defender for IoT connects to both cloud and on-premises components and is built for scalability in large and geographically distributed environments. Defender for IoT systems includes the following components:

  • The Azure portal, for cloud management and integration to other Microsoft services, such as Microsoft Sentinel

  • Network sensors, deployed on either a virtual machine or a physical appliance. You can configure your OT sensors as cloud-connected sensors, or fully on-premises sensors.

  • An on-premises management console for cloud-connected or local, air-gapped site management.

  • An embedded security agent (optional).

Security recommendations triggered by Defender for IoT will be surfaced in Defender for Cloud dashboard, as shown in the example below:

Screenshot showing security recommendations in Microsoft Defender for Cloud dashboard.

It's also important that you can integrate the threat detection generated by your security IoT solution with your SIEM solution. Microsoft Sentinel and Microsoft Defender for IoT help to bridge the gap between IT and OT security challenges, and to empower SOC teams with out-of-the-box capabilities to detect and respond to OT threats efficiently and effectively. The integration between Microsoft Defender for IoT and Microsoft Sentinel helps organizations to quickly detect multistage attacks, which often cross IT and OT boundaries.