Closing the Security Gap in Industrial IoT: Protecting Legacy Systems in a Connected World

Closing the Security Gap in Industrial IoT: Protecting Legacy Systems in a Connected World

Industrial IoT adoption is accelerating, driven by the promise of real-time insights, automation, and operational efficiency. Across sectors like manufacturing, energy, and smart infrastructure, organizations are connecting more equipment than ever before. But in the rush to connect, one critical reality is too often overlooked: much of the installed base of industrial hardware was never designed for networked operation.

When these legacy systems are exposed to modern networks without proper safeguards, they create an expanded attack surface — one that determined adversaries can exploit. Bridging the gap between decades-old technology and today’s connectivity standards is not straightforward, but it is fast becoming a top-tier cybersecurity priority.

Understanding the Risk

Many industrial control systems, sensors, and programmable logic controllers in active use today predate the era of IP-based networking. They were engineered for isolated, closed environments, often without built-in authentication, encryption, or intrusion detection.

Once connected to enterprise networks or the internet, these devices can unintentionally provide an entry point for attackers. We’ve seen incidents where outdated protocols without encryption have been intercepted, or where default device credentials — never changed since installation — were used to gain unauthorized access.

The stakes are especially high in industrial contexts. Disruptions can halt production lines, damage equipment, or in the case of critical infrastructure, impact public safety. The growing integration of AI-driven analytics and remote management tools only heightens the importance of ensuring that the edge is secure from the outset.

Common Pitfalls

Organizations often underestimate the complexity of securing legacy OT environments. Some of the most frequent missteps include:

• Flat network architecture that allows a compromise in one area to spread unchecked.
• Unpatched firmware on devices that cannot easily be updated, leaving known vulnerabilities exposed.
• Vendor remote access arrangements without strict controls, which can serve as unmonitored back doors.
• Lack of network segmentation between OT and IT systems, making it easier for attackers to move laterally.

Addressing these issues requires more than a checklist approach — it demands a holistic security strategy tailored to the realities of industrial environments.

Building a Resilient Security Framework

A layered, defense-in-depth strategy offers the best protection. This means applying security controls at every stage of the data path, from the device itself to the cloud applications consuming its data. Key elements include:

• Protocol translation and encryption to secure data traveling from legacy devices.
• Certificate-based authentication for both devices and applications.
• Continuous monitoring to detect anomalous activity at the edge before it escalates.
• Strong segmentation so that critical OT assets remain insulated from IT network breaches.

A new generation of Edge computing platforms can play a pivotal role here. By securely interfacing with older equipment, performing local processing, and enforcing security policies at the edge, they can help organizations modernize without exposing themselves to unnecessary risk.

Both commercial and open-source, industrial grade, edge platform implementations have emerged over the last few years and have reached a level of maturity where they are being used successfully in large scale production deployments.

For example, a key open-source initiative with broad cross-industry support is the Linux Foundation’s LF Edge. The objective of LF Edge is to establish an open, interoperable framework for edge computing. EdgeX Foundry is one of the largest projects under the LF Edge umbrella. It provides a flexible and scalable open software platform that facilitates secure interoperability between OT devices, applications at the edge and IT/Cloud services.

Managing Security at Scale

Protecting one or two facilities is challenging enough; extending that protection across dozens or hundreds of sites requires scalable management. This includes centralized orchestration of security updates, configuration changes, and access policies, as well as consistent enforcement of best practices in every location.

Forward-looking operators are also aligning with international standards such as IEC 62443, which provides a comprehensive framework for securing industrial automation and control systems.

Moving Forward

The industrial sector’s digital transformation depends on connecting systems that were never intended to be connected. The benefits are substantial, but so are the risks. Treating security as an afterthought invites avoidable vulnerabilities that can undermine the entire initiative.

The good news is that with careful planning, modern tools, and a layered approach, organizations can integrate legacy systems into IIoT architectures without sacrificing safety or reliability. The time to act is now — before the next connection inadvertently becomes the next breach.

About the author

This article was written by Andrew Foster. He is Product Director at IOTech, with over 20 years of experience developing IoT and Distributed Real-time and Embedded (DRE) software products. He has held senior roles in Product Delivery, Management, and Marketing, and frequently speaks at industry conferences on distributed computing, middleware, embedded technologies, and IoT. Andrew holds an M.S. in Computer-Based Plant and Process Control and a B.Eng. in Digital Systems.