Why Secure Remote Access Is the Biggest Risk in Operational Technology Today
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Industrial environments were never designed for the world they now operate in. Pipelines, power substations, manufacturing plants, water treatment facilities, and maritime systems were built to run reliably and continuously. For decades, reliability meant isolation. Systems were physically separated and access was local.
Today, that reality has changed. Engineers troubleshoot systems remotely. Vendors maintain equipment from across the country. Integrators deploy updates without setting foot onsite and remote connectivity has become essential to keeping operations running. It has also quietly become one of the most significant sources of risk facing operational technology (OT) environments. Remote access has expanded not because organizations wanted it to, but because modern operations depend on it.
Remote access often arrives in the form of virtual private networks (VPNs). They are familiar, widely deployed, and easy to implement. But in OT environments, a VPN does more than enable connectivity. It effectively extends the internal network perimeter outward. A remote laptop connecting through a VPN can function like a very long network cable plugged directly into critical systems. If that remote device is compromised, malware can move along that connection into environments that were never designed to defend against hostile traffic.
Read More: The Agentic SOC: Why Security Operations Must Reimagine Itself—and Fast
This risk is amplified by the operational realities of OT. Vendors, contractors, and integrators often require access and credentials which are often shared. Access persists long after a project ends. Visibility into who connected, what they accessed, and why is frequently limited or nonexistent. In many environments, access exists because it always has.
The lessons of Ukraine still apply
The 2015 cyberattack on Ukraine’s power grid marked a turning point. It demonstrated that cyber operations could disrupt physical infrastructure and affect daily life on a massive scale. More importantly, it showed that attackers were willing to study industrial environments and target operational systems directly.
Since then, attackers have refined their playbooks. They research specific devices and operational workflows in order to exploit weak authentication and default credentials. In some cases, they simply log in. Increasingly, attackers exploit legitimate access pathways rather than attempting to breach hardened perimeters. The tactics are not always sophisticated, but they are often effective.
Part of the reason is that OT systems were never built for today’s threat model. Unlike traditional IT environments, many industrial devices were engineered for longevity, stability, and predictable operation, not cybersecurity resilience. Some controllers still ship with default credentials, which are not required to be changed at first login. Many lack meaningful logging or authentication controls. Others can become unstable when subjected to routine IT security scanning. Applying common IT security practices can disrupt operations rather than protect them.
When something fails in OT, recovery is rarely quick as its IT counterpart. Restoring service may require sending a technician into the field and manually resetting equipment. That delay can affect production and safety. These constraints shape every security decision.
Vendor relationships complicate security
OT operators depend heavily on vendors to maintain and support specialized systems. Yet vendors often control patch timelines, software compatibility, and upgrade paths.
Some systems cannot be patched without voiding support agreements. Others rely on outdated operating systems that cannot be upgraded without costly redesign. In response, organizations freeze systems in place to preserve reliability. Over time, that decision increases exposure. Security becomes a negotiation rather than a technical control.
Many organizations are still working to understand what actually exists in their environments.
They may not know:
-how many remote connections are active
-which vendors have access
-who is logging in
-what devices are being accessed
-what is being done on those devices during a session
-whether access is still required
Without visibility, meaningful security is impossible. Understanding assets and access patterns is the first step toward reducing risk. Regulators and auditors increasingly expect organizations to demonstrate control over remote access, not just document that connections occurred.
Progress is happening, but it’s uneven
The industry is evolving and some operators are moving away from broad VPN access toward more controlled connectivity models. Others are implementing approval workflows, audit logging, and role-based access controls. Zero Trust principles and network segmentation are becoming more common. These changes can improve security and provide operational insight, and organizations often discover unknown connections and unnecessary access once visibility improves.
Read More: When Telecom Infrastructure Starts to Behave Like Enterprise Software
Still, progress is uneven. Some environments continue operating under assumptions formed decades ago. In critical infrastructure, complacency is dangerous and defenders must be right every time. Attackers only need one opportunity.
What operators should prioritize now
Improving OT security does not require immediate transformation. It requires focus.
Understand what exists.
Inventory assets and map access pathways. Identify who connects, how they connect, and why.
Reduce unnecessary connectivity.
Remote access should exist only where it is justified and controlled.
Improve access governance.
Implement approval workflows, audit trails, and least-privilege access.
Engage vendors differently.
Security expectations must be explicit, even when system lifecycles are long.
Plan for lifecycle security.
Organizations should understand how devices will be updated, maintained, and secured years into the future.
Critical infrastructure now sits at the intersection of cybersecurity and geopolitics. Nation-state actors invest heavily in reconnaissance and targeting of infrastructure systems. Utilities and operators must defend against adversaries with significant resources and clear strategic objectives. This reality raises the stakes but also clarifies priorities. The goal is resilient operations.
Remote access is now foundational to OT security
Secure remote access is more than a convenience. It is a prerequisite for protecting critical infrastructure and the communities that depend on it. VPNs made remote connectivity possible, but they were never designed to govern continuous third-party interaction with critical systems. That responsibility now belongs to the organizations that operate and defend them.
