Operational technology (OT) environments in critical infrastructure have become prime targets for sophisticated cyber attackers. For municipal utilities, the challenge is clear: protect essential services while managing rapid digitalisation and increasing connectivity.
Recent figures highlight the urgency. Ransomware attacks on OT systems rose significantly in early 2025, driven by familiar weaknesses—outdated firmware, insecure protocols, limited segmentation and insufficient monitoring. Attackers continue to exploit these gaps to access control systems and disrupt operations.
The impact extends far beyond downtime. Compromised smart meters, for example, can expose sensitive energy usage data and reveal behavioural patterns, creating both privacy risks and compliance issues. As utilities expand their use of sensors, cloud platforms and automation, they also increase their attack surface. Without strong authentication and segmentation, even isolated assets can become entry points for remote attacks.
Emerging technologies introduce further risks. Smart metering relies on continuous data exchange, making it vulnerable to manipulation that could affect billing or grid stability. Networked EV charging infrastructure presents similar challenges, with potential exposure of user data and control systems.
The greatest complexity comes with sector coupling, where energy, water and transport systems are interconnected. In these environments, a single successful attack can trigger cascading failures across multiple services.
Regulation Is Raising the Bar
Regulation is accelerating the need for stronger OT security. NIS2 requires utilities to implement robust risk management and incident reporting, while IEC 62443 provides practical guidance for securing industrial systems. The Cyber Resilience Act complements this by pushing vendors to deliver more secure products.
Together, these frameworks set clear expectations: utilities must take ownership of their security posture, implement structured controls and ensure their supply chain does not introduce unnecessary risk.
Building a Resilient OT Security Strategy
A strong OT security strategy starts with network segmentation. Separating IT and OT systems—and dividing OT into secure zones—limits the spread of attacks and protects critical assets more effectively.
Securing remote access is equally important. External connections for maintenance must be tightly controlled through multi-factor authentication, time-limited permissions and privileged access management. Comprehensive logging ensures full visibility and traceability.
Continuous monitoring plays a central role. Network Detection and Response (NDR) solutions help identify anomalies early, especially when integrated with IT security systems. This creates a unified view of threats across the organisation.
Patch and vulnerability management remains challenging, particularly with legacy systems. Where updates are difficult, virtual patching and compensating controls can reduce risk. Maintaining a clear asset inventory and monitoring known vulnerabilities are essential steps.
Resilience planning is also critical. Utilities should define clear incident response processes, maintain fallback options such as manual operations and regularly test their readiness through simulations.
Security Is as Much About People as Technology
Technology alone is not enough. Strong governance, compliance with standards such as ISO 27001 and secure procurement practices are essential to ensure consistent protection across the organisation and its supply chain.
Equally important is building awareness among employees. Targeted training enables operators and engineers to recognise threats and respond effectively. Embedding security into daily operations strengthens the overall security culture.
From Obligation to Strategic Advantage
OT security is no longer optional—it is fundamental to maintaining reliable infrastructure. Utilities that combine modern security architectures with strong processes and skilled teams can withstand increasingly sophisticated attacks.
By aligning regulatory requirements with practical implementation and fostering a culture of security, they move beyond compliance and build lasting resilience in a rapidly evolving threat landscape.
Now is the time to act. Assess your current OT security posture, identify critical gaps and prioritise the controls that will deliver the greatest impact. By working with experienced cybersecurity partners and adopting proven frameworks, utilities can accelerate their journey to resilience—before attackers force the issue.
