Continuous Threat Exposure Management in OT Security for a Safer Future

Cyber security in operational technology (OT) has entered a new era. Ransomware groups are now deliberately targeting industrial systems, while the convergence of IT and OT networks has created a growing list of access points for attackers to exploit. Traditional methods such as annual risk assessments or occasional penetration tests are no longer sufficient. Organisations need a framework that reflects the continuous nature of these threats.

This is why Continuous Threat Exposure Management (CTEM) is gaining attention in the OT world.

What CTEM Really Means

CTEM is not a single product or a checklist but a cyclical approach to managing exposure. It rests on five core stages:

• Scoping defines what is most important to protect, from supervisory control systems in energy to distributed control systems in manufacturing.
• Discovery is the ongoing process of finding exposures, whether it be a vulnerable legacy device, a misconfigured remote access point, or an unknown asset plugged into the network.
• Prioritisation ensures that not all risks are treated equally but ranked according to their potential impact and the likelihood of exploitation.
• Validation tests whether existing defences truly work, often by simulating realistic attack paths in a safe and controlled way.
• Mobilisation then puts plans into action, applying patches, tightening access controls, or deploying compensating measures before the cycle begins again.

The strength of CTEM lies in its continuity. Rather than waiting for the next audit to uncover weaknesses, the framework keeps exposures under constant review.

Why OT Needs a Continuous Approach

OT is a unique environment where the risks are not only financial but operational and even physical. Many assets remain in service for decades and were never designed with security in mind. Patching them is complex, and downtime for updates is often unacceptable. Yet attackers do not pause while organisations wait for maintenance windows.

Recent industry research underlines this urgency. IBM’s 2025 X-Force report revealed that nearly half of OT vulnerabilities disclosed in the first half of the year were rated high or critical, and more than 20% already had publicly available exploit code. In other words, exposures in OT are not theoretical—they are live and accessible to adversaries. CTEM addresses this by reducing the time between exposure and remediation.

Putting CTEM into Practice in OT

For many organisations, the first step in CTEM is simply to establish visibility. You cannot manage what you cannot see, and OT networks often harbour “shadow assets” — devices connected without the knowledge of security teams. A famous case involved a rogue Raspberry Pi connected to a production network, creating a stealth backdoor. It was only detected through advanced monitoring that aligned closely with the discovery phase of CTEM.

From there, prioritisation ensures that the exposures with the greatest potential impact receive immediate attention. For example, a misconfigured remote access service may be a more urgent priority than an outdated sensor that has no external connectivity. Validation can then demonstrate whether existing access controls, segmentation, or authentication methods truly stand up to attack scenarios.

Mobilisation closes the loop. This may involve patching where possible, adjusting identity management, or in some cases, deploying compensating controls that limit exposure without requiring downtime. What matters most is that lessons learned are fed back into the cycle, keeping the process alive and adaptive.

The Road Ahead

The real value of CTEM for OT lies not in replacing existing practices but in transforming them into something living and continuous. By adopting this mindset, organisations shorten exposure windows, strengthen compliance with regulations such as NIS2 and the Cyber Resilience Act, and most importantly, build resilience against increasingly sophisticated attacks.

The shift from reactive defence to proactive exposure management is not a trivial one, but it is becoming essential. The threats facing OT are constant; the defences must be equally relentless. For critical infrastructure and industry, CTEM represents more than a framework — it is a path towards a safer and more resilient future.