Securing Operational Technology: Why Visibility-Led Scanning Is Now a Business-Critical Priority

Operational Technology (OT) environments are rapidly becoming one of the most targeted and misunderstood areas of cyber security.

Account Manager Ben Williams and Cyber Security Consultant Holly Ellwood explain what OT really is, why the threat landscape has changed and how organisations can safely begin securing these highly sensitive environments. This article brings those insights together into a practical, search-optimised guide for organisations looking to strengthen their OT security posture.

Operational Technology refers to the physical systems that keep an organisation running.

Unlike traditional IT systems, OT directly controls real-world processes, such as manufacturing lines, utilities infrastructure and production equipment. Typical OT environments include:

• Automotive manufacturing systems
• Water and utilities control systems
• Food production and processing environments

These systems sit outside of the traditional corporate IT estate and are often located on factory floors or within industrial facilities. Their primary purpose is not data processing, but controlling physical processes that directly impact service delivery and safety.

For a widely recognised industry definition of Operational Technology, IBM provides a helpful overview of what operational technology (OT) is and how it differs from IT.

A key distinction between IT and OT cyber risk is the impact of a successful attack.

In IT environments, incidents typically focus on:

• data theft
• ransomware
• loss of confidentiality

In OT environments, the primary risk is disruption and safety.

For example, in a utilities environment, compromising systems that control chemical dosing within water treatment can directly affect public health. This makes OT security not only a cyber issue, but a business continuity and human safety issue. This shift from purely data-driven impact to physical and safety-driven risk is one of the reasons OT security has become a board-level concern.

The UK National Cyber Security Centre (NCSC) offers detailed guidance on securing industrial control systems and operational technology environments.

Many OT systems were designed and installed decades ago.

They were never built with:

• internet connectivity
• corporate IT integration
• modern cyber security controls in mind.

As organisations have connected production networks to business systems, cloud services and remote access solutions, these legacy environments have become increasingly exposed, while still lacking the security mechanisms found in modern IT platforms.

The US Cybersecurity and Infrastructure Security Agency (CISA) highlights this challenge and provides best practice guidance for operators of legacy and modern industrial systems through its Industrial Control Systems security programme. 

Before organisations can protect OT systems, they must first understand exactly what is connected to their industrial networks.

Holly explains, security in OT always starts with visibility:

You can’t secure what you can’t see.

Understanding what assets exist within the OT environment is critical, which makes OT-safe discovery and scanning essential.

In practice, this challenge is driven by:

• undocumented systems
• ageing equipment
• unknown firmware and software versions
• limited configuration records

In standard IT environments, vulnerability scanners actively probe systems to identify weaknesses.

In OT environments, this approach can be highly disruptive.

The industrial protocols used by OT devices are fundamentally different from traditional IT protocols, and aggressive scanning techniques can:

• overload fragile controllers
• interrupt operational communications
• cause devices to drop off the network

In short, traditional vulnerability scanning can create the very operational disruption organisations are trying to avoid.

To safely discover and understand OT assets, organisations must use tools designed specifically for industrial environments.

Holly highlights tools such as Tenable and runZero as examples of platforms that approach scanning differently.

Rather than using traditional IT probing techniques, these tools:

• communicate using OT-specific protocols
• perform lightweight active or passive discovery
• safely identify devices without disrupting production systems

This allows organisations to build an accurate and continuously updated asset inventory while minimising operational risk.

Once organisations understand what is connected to their OT network, the next step is exposure management.

This moves beyond creating an asset list and focuses on understanding:

• how OT systems can be accessed
• what potential attack paths exist
• how an attacker could move between IT and OT environments

Because many OT devices cannot be patched directly, it becomes essential to identify surrounding systems — such as engineering workstations, jump servers and network infrastructure — that can be hardened to reduce risk.

A well-recognised framework for understanding adversary behaviour in industrial environments is the MITRE ATT&CK for ICS matrix, which outlines real-world attack techniques targeting industrial control systems.

OT security is no longer a niche technical concern.

It directly affects:

• operational continuity
• regulatory and compliance obligations
• employee and public safety
• organisational reputation

As industrial environments become increasingly connected, organisations that invest early in:

• safe OT asset visibility
• OT-aware scanning and discovery
• exposure-driven remediation strategies

will be significantly better positioned to prevent disruptive incidents.

At Celerity, our cyber security specialists work closely with engineering, operational and IT teams to help organisations:

• gain safe and accurate visibility across OT environments
• deploy OT-aware discovery and monitoring tools
• identify attack paths and exposure across IT and OT
• create practical, low-disruption remediation roadmaps

If your organisation is beginning its OT security journey — or struggling with legacy systems and limited visibility — Celerity can help you take the first step safely and confidently.

Contact Celerity today to discuss your OT security assessment and discovery services.