It has been many years since industrial organisations could rely on the security of air-gapped networks.

Historically, security within industrial environments was predominantly physical. Protection was centred on fences, barriers, security guards and isolated Operational Technology (OT). But today, these ring-fenced environments are rapidly becoming a thing of the past.

OT is now routinely interconnecting well beyond industrial borders to support efficiency, enhance operations, improve plant safety and reduce costs. Yet while this connectivity delivers clear operational benefits, it also exposes industrial systems to threat actors operating in the digital domain.

Unlike physical threats, these attackers cannot simply be kept out with fences or restricted perimeters.

Instead, organisations must defend every digital access point that could be exploited to gain entry into OT environments. However, as automation and connectivity continue to expand across industrial networks, these potential entry points are increasing significantly.

However, even despite this growing risk, many industrial organisations remain at an early stage in their OT security journey, potentially leaving their critical systems exposed.

While progress is being made, improvements are not consistent across the industry. Some organisations remain hesitant to introduce additional security controls into operational environments. In many cases, operators prioritise reliability and simplicity above all else, favouring systems that “just work” rather than systems that work securely.

The unique challenge of OT environments

One of the biggest challenges in securing OT environments comes down to visibility.

Industrial systems are often installed by external vendors and maintained over long operational lifecycles. Operators are trained to run the systems, rather than understand their internal architecture. Meanwhile, the IT teams that are often assigned the task of securing OT often lack the specialised expertise required to interpret industrial protocols or control systems.

The result is a visibility gap where neither operations teams nor IT security teams have a complete picture of how the environment functions.

When this happens, security teams can struggle to detect abnormal behaviour or recognise when a compromise may be taking place.

In many industrial environments, organisations also lack a complete inventory of the assets operating on their networks.

New equipment may be installed by suppliers or contractors with little involvement from central IT teams. Devices such as sensors, controllers and robotic systems may be added to production lines without being fully documented within the wider security architecture.

This lack of visibility makes it difficult for organisations to answer some fundamental security questions:

What devices are connected to the network?
How are they communicating?
Who has access to them?
Are they behaving as expected?

Without answers to these questions, it becomes extremely difficult to detect threats or enforce meaningful security controls.

This is why visibility is increasingly seen as the first and most critical step in securing OT environments.

Technologies that analyse network traffic and observe communications between devices can provide organisations with a real-time understanding of activity across industrial networks. By monitoring interactions between systems, organisations can build an evolving map of devices, relationships and behaviours.

From there, security teams are far better positioned to identify anomalies or suspicious activity.

Managing access and third-party risk

Visibility is equally important when managing external access to industrial systems.

Many OT environments rely heavily on suppliers and partners to maintain or troubleshoot equipment. These third parties often require remote access to industrial systems, which can introduce significant security risks if not carefully controlled.

In some cases, suppliers may retain persistent or unrestricted access to sensitive systems. If those external organisations are compromised, attackers could potentially gain entry into industrial networks through those connections.

Access management technologies can help mitigate this risk.

By routing third-party access through controlled platforms and monitoring external activity, organisations can significantly reduce the likelihood of unauthorised behaviour while still enabling essential maintenance and support.

You can’t protect what you can’t see

Despite growing awareness of the issue, OT security maturity still varies widely across industries and organisations.

Some organisations are already implementing advanced controls and monitoring capabilities. Others are only beginning to address the challenges associated with securing connected industrial environments.

However, one point is becoming increasingly clear: securing operational technology begins with understanding it.

Before organisations can enforce policies, detect threats or manage risk, they must first gain visibility into their environments.

Because in OT, just as in IT, it is impossible to protect what you can’t see.