Thought about OT systems' complexity for 8 seconds.

Thoughts on Complexity in OT Systems

Anyone discussing OT often focuses on PLCs when mentioning ICS. Occasionally, someone goes further and brings up SCADA. Yet, it is rare to find discussions diving deeper into DCS. Why does this happen? Some believe DCS is more complex and specialized, while others argue that SCADA is more challenging due to its broad coverage and intricate networks. The reality can differ significantly from simplified descriptions found in standard references. Actual sites rarely fit neatly into textbook definitions.

At large O&G facilities, a single DCS may connect to multiple other DCS implementations, each serving different plants within the same complex. Each of these DCS layers may oversee SCADA systems tied to RTUs, wellheads, compression stations, and other remote assets. These SCADA systems feed their data back into the main DCS, which can then adjust setpoints. SCADA systems incorporate PLCs, and a DCS might handle multiple SCADA networks. This interconnected design ensures high availability and operational continuity despite geographic distances and complexity. If the main control layer is compromised, individual systems can still run independently, maintaining production and safety.

Risk-Based Design and the Overlooked Cyber Dimension

Process control design is firmly rooted in risk-based engineering. The placement of control valves, shutdown valves, bypass valves, and the hierarchy of alarms and shutdowns often emerge from HAZOP studies, cause-and-effect charts, operational experience, operation manual, and vendor recommendations. These analyses guide how protections are assigned, what logic goes into DCS and ESD, and which valves fail open or fail close. It is a comprehensive process built on decades of field experience and iterative improvement.

One critical point frequently overlooked is that while HAZOP processes consider disruptions in signals, power, air supplies, and other physical factors, they do not always explicitly account for cyber scenarios. Yet, if a team knows how to mitigate failures of signals and instruments, it can also treat cyber manipulation as another failure mode. They can add logic in the DCS and ESD to verify consistency, deploy redundant measurements, and ensure that if one reading is corrupted, another can be trusted. The same robust engineering principles that handle conventional failures can be extended to cyber threats. In this way, integrating cyber considerations into long-established frameworks is not a radical departure, merely a natural evolution.

Why Cyber Events May Go Unnoticed

In environments dominated by OT, cyber-related events often blend seamlessly into the daily noise of technical glitches and instrument failures. Process teams may see a suspicious anomaly but treat it like any other system disruption and fix it without labeling it a cyber event. Another factor is that these environments often have multiple layers of process protections. Different kinds of shutdown levels exist, and operators have detailed procedures guiding them through unusual scenarios.

At one large onshore gas plant producing hundreds of millions of cubic feet per day plus condensate, an issue linked to a vendor-deployed security patch caused a loss of visibility from DCS HMIs. Within minutes, operators spread out to predetermined locations and ran the plant in fully manual mode for two hours. ESD remained intact, and the contingency plan allowed up to three hours of manual operation with the right personnel. Production continued safely. If such an event were cyber-related, it might still be addressed simply as a technical hiccup. Only repeated or well-documented cyber attacks, such as certain high-profile incidents, draw sustained attention. Many single incidents vanish into the operational background.

Gaining Credibility in OT: Field Insight Over Screens

Newcomers to OT security should first prioritize understanding OT systems in practice. Reading about DCS, SCADA, PLC, or ICS in training materials is not enough. Gaining meaningful insight requires on-site exposure. Observing processes firsthand, talking to operators, and understanding what actually happens in the field are non-negotiable steps.

Without this effort, anyone trying to convince operators or managers to adopt certain security measures will seem out of touch. The reasoning behind recommended changes will not resonate, as it fails to align with day-to-day realities. The same holds true for OEM system engineers who remain confined to control rooms or staging facilities. Without field exposure, reliance on what is displayed on HMIs or network diagrams creates an incomplete picture. Operators who have worked in the field for years or decades can immediately identify outsiders who do not understand actual conditions. Building trust hinges on speaking the same language as those who run the equipment and keep production flowing.

Leveraging Process Control Expertise in Cybersecurity

Engineers with process control backgrounds have a distinct advantage when transitioning into OT security. They already understand how these systems operate, why certain setpoints matter, and how logic, instrumentation, and equipment interact. They know what ESD layers do and why SCADA interacts with DCS in a particular way. They are the best guardians of their operations because they have been involved in running them, tuning them, and ensuring they function optimally.

OT, as encountered in the field, often proves simpler than the complexity conjured in marketing slides or theoretical models. Some consultants build narratives that create a sense of overwhelming dependency on their expertise. This can be avoided. A sound approach encourages independence and knowledge transfer, guiding teams to solve their own problems and adapt their systems to new threats. Instead of pushing customers to rely on external service providers indefinitely, a worthy partner educates and supports until the operation stands on its own.

Becoming Independent and Strengthening the Human Factor

Being independent in OT security involves understanding the intricacies of DCS, SCADA, PLC, ICS, and other systems without constant external intervention. It means knowing how ESD logic, cause-and-effect charts, vendor packages, and HAZOP insights shape the automated layers. It also means acknowledging human expertise. Operators can switch to manual mode, find workarounds, and maintain safe production even when screens go dark. This interplay of human skill and engineering design provides natural resilience.

The lack of daily sensational headlines about cyber incidents in these environments might stem from this built-in resilience. Standard engineering designs and operator prowess already incorporate contingency strategies. Even without labeling these efforts as “cyber,” they serve to mitigate a wide range of disruptions. Humans remain integral to the loop, and their presence often represents a critical, if understated, security layer.

Moving Beyond Purely Technical Solutions

Many consultants approach OT security as a purely technical problem. They emphasize network segmentation, firewall rules, detection systems, and sophisticated monitoring tools. While these elements have their place, what value do they provide if the operators who will approve them cannot understand their rationale or if they disrupt the delicate balance of control logic?

True OT security recognizes that technical defenses must integrate seamlessly with daily operations. Recommendations should reflect how SCADA, DCS, PLC, and ICS networks interact. They should align with vendor-specific logic, acknowledge established risk assessments, and respect the overlapping roles of ESD and other protective layers. Security improvements that ignore these operational nuances risk eroding trust and causing confusion rather than strengthening defenses.

On-Site Presence and Building Trust

If those entering OT security spend enough time on-site, they will witness the complexity firsthand. This experience enables them to propose measures that align with actual conditions rather than theoretical assumptions. Such an approach builds trust, as operators, engineers, and managers see that suggested solutions consider their constraints and do not threaten production or stability.

Initiatives like adding logic to detect manipulated signals, introducing redundancy in instrumentation, or preserving the ability to run manually if something goes wrong in the main control add tangible value. They fit naturally into existing workflows. Operators appreciate solutions that complement established safety layers and align with their training and experience. Such measures do not spark resistance because they are not imposed from afar; they emerge from understanding what is already in place.

Choosing the Right Partners

When looking for OT consultants, favor those who refuse to remain distant. Those who take the time to ask questions in the field, talk to operators, and understand what happens beyond the DCS and SCADA screens are far more likely to offer lasting value.

The ideal OT cybersecurity consultant should empower you rather than create dependency. They should also simplify security. They know that ICS and process control engineers have long adapted systems to new operational challenges and can adapt to new threats as well.

A Seamless Integration of Cyber and Operational Realities

In the end, stepping into OT security is not about adopting new buzzwords or inflating complexity. It is about merging proven engineering practices with an awareness of digital threats. The complexity surrounding DCS, SCADA, PLC, and ICS often simplifies when viewed through direct process understanding.

The greatest impact will come from those willing to learn the process, engage with operators, and embrace the actual conditions. By doing so, OT security integrates smoothly, enhancing safety and continuity without unnecessary hype. This approach leads to practical, sustainable improvements that reflect the true nature of OT environments. It is a path to resilience, independence, and trust that stands firm against physical and digital challenges.