Securing the edge: OT cybersecurity moves from IT afterthought to operational priority

For years industrial control systems operated behind closed networks, quietly powering essential infrastructure. While isolation once offered protection, today’s digital transformation is steadily eroding that boundary.

In its 2025 OT Cybersecurity Action Guide, Dragos reported a record 905 vulnerabilities in industrial control system (ICS) technologies globally — a 20% increase over the previous year. More alarmingly, the Asia-Pacific region saw the largest rise in targeted activity by OT-specific threat groups. The message is clear: cyber risks are no longer confined to the IT domain.

OT environments differ significantly from IT networks: where IT focuses on data confidentiality, OT prioritises uptime, safety and process integrity. Most legacy systems were developed in isolation, never anticipating today’s levels of digital integration, and introducing traditional cybersecurity tools can inadvertently impact performance or availability.

Legacy devices often run on proprietary protocols and outdated firmware, making them difficult — or impossible — to patch. In some cases, security updates may be avoided entirely for fear of disrupting critical operations.

Industrial systems weren’t designed for connectivity, but they need cybersecurity as if they were. This presents a dilemma for organisations: how do you secure a system you can’t afford to interrupt?

Visibility is the first step

Cybersecurity starts with network awareness — yet in many OT environments, insight into connected assets remains limited. Organisations often don’t have a complete inventory of their connected assets, from device types and firmware versions to communication flows. Without this foundational understanding, it’s nearly impossible to assess risk or respond effectively to a threat until it’s too late.

Establishing visibility involves identifying devices, understanding how they communicate, and assessing where the weak points lie. This allows for prioritised action and informed decision making, rather than reactive fixes when something goes wrong.

Mapping the network is also a necessary first step for complying with standards such as IEC 62443, which emphasise structured, risk-based approaches to securing industrial systems.

The shift from isolation to segmentation

Historically, ‘security through obscurity’ or complete isolation (air-gapping) was the norm in OT, but today that’s rarely feasible. Industrial systems now interact with enterprise software, remote maintenance teams, cloud platforms and supply chain partners.

Rather than cutting systems off entirely, modern strategies aim to separate them intelligently. Network segmentation allows operators to group systems by function or risk level, reducing the likelihood that a single vulnerability will compromise the entire environment.

This approach (commonly known as defence in depth) adds layers of protection and makes it significantly harder for threats to move laterally if they do gain access.

Balancing connectivity with control

Remote access is now a fact of life in industrial operations. Whether for diagnostics, software updates or vendor support, external connectivity is often necessary to maintain uptime and efficiency. But it must be done securely.

Best practice involves tightly controlled access based on user identity and role. Encryption, multifactor authentication and audit logging are becoming standard, ensuring that only the right people can access the right systems at the right time.

When designed thoughtfully, secure remote access can deliver the flexibility teams need — without compromising system integrity.

Aligning with standards and global best practice

Regulatory pressure is also intensifying. Australia’s Security of Critical Infrastructure Act (SOCI) and international standards like IEC 62443 are pushing industrial organisations to adopt formal risk management processes for OT environments.

NHP works closely with customers to help them align with these frameworks — not just at the documentation level, but in their system design, asset selection and long-term lifecycle planning. Our Cybersecurity Assessment Services, delivered in partnership with Rockwell Automation, provide a structured approach to identifying gaps and building a roadmap for improvement.

A strategic approach to industrial cybersecurity

Cybersecurity isn’t a one-size-fits-all solution. Every facility has its own architecture, legacy constraints and operational needs. Through our partnerships with Rockwell Automation and HMS Networks, we help organisations assess risk, identify gaps, and implement practical controls without compromising performance. Our tailored approach aligns with recognised standards and is informed by hands-on experience across Australian industry.

The focus is on sustainable improvements, not just short-term fixes. Whether it’s visibility, secure network design or segmenting legacy assets, resilience comes from embedding cybersecurity into the foundations of industrial operations.

As threat landscapes evolve, so too must the mindset. OT cybersecurity is no longer an afterthought. It’s a foundational pillar of modern industrial operations — and those who act now will be better equipped to withstand what comes next.

Not sure where to start? Don’t wait for a breach to find out what’s at risk.

NHP’s Installed Base Evaluation (IBE) gives immediate insight into what’s connected, what’s outdated and where vulnerabilities lie. It’s the fastest way to take control and start securing your operations.

Book your IBE today at https://www.nhp.com.au/Services/Field-Services.

Image credit: iStock.com/Smederevac