The Changing Landscape of OT Cybersecurity
For decades, cybersecurity strategies operated under a simple assumption: anything inside the network perimeter could be trusted (aka the Castle and Moat theory). For OT networks, this approach worked when they were isolated and self-contained. But with the increasing interconnectivity of IT and OT systems, the threat landscape has evolved. Applying a “Zero Trust” security model to your OT network is a response to this shift, and it’s based on the principle of “never trust, always verify.”
If you’ve had much exposure to IPsec, you’ll have heard this term a lot lately. Zero Trust assumes that every access request—whether from inside or outside the network—could be malicious. So instead of granting broad permissions based on a user’s location or previous authorization, every device, user, and connection must be continuously authenticated and authorized.
For OT networks, which support critical infrastructure like HVAC, lighting, security systems, and industrial processes, this means enforcing strict access controls and micro-segmentation to prevent lateral movement of threats. As OT systems become more complex and interconnected, the need for a Zero Trust approach has never been more critical.
Sound complex? With the right tools and teams, it doesn’t have to be.
How Did Zero Trust Evolve for OT?
The Zero Trust model was introduced in 2010 by John Kindervag, a Forrester Research analyst, who recognized the fundamental flaws in traditional network security models. Since then, Zero Trust has gained traction across industries, driven by a rise in cyber threats, particularly in critical infrastructure and industrial control systems.
The concept of Zero Trust security has migrated from IT security architecture as a response to growing vulnerabilities in OT network security, particularly with the increased connectivity of OT systems to IT networks and the internet. Traditionally, OT networks operated in a closed environment, relying on perimeter-based security measures like firewalls. But today, IT/OT convergence, cloud computing, and remote access have exposed these systems to new risks. High-profile attacks like Stuxnet demonstrated the potential devastation of breaches in industrial environments overseen by OT networks.
Legacy OT systems present unique challenges, as many were designed without consideration for modern security threats. Perimeter security alone cannot protect against threats that emerge inside networks through compromised credentials or insider activities.
Benefits of Zero Trust in OT Networks
Zero Trust implementation delivers several key advantages for operational technology:
- Reduced Attack Surface: Strict access controls block unauthorized devices and users
- Prevention of Lateral Movement: Even if one device is compromised, attackers cannot easily reach other systems
- Enhanced Access Controls: Multi-factor authentication and least privilege principles ensure only authorized personnel interact with critical assets
- Improved Compliance: Helps meet industry standards like NERC CIP and NIST guidelines
- Minimized Downtime: Prevents security incidents from causing operational disruptions
- Strengthened Resilience: Maintains functionality even during security events
- Secure Remote Access: Enables strictly controlled connections for necessary maintenance and monitoring
Unique Challenges of Implementing Zero Trust in OT Networks
Unlike IT environments, OT networks rely on a hodge-podge of legacy systems and mission-critical infrastructure that may not integrate well with IT security interventions. Implementing Zero Trust in OT requires an awareness of the unique challenges that may come up, including:
- Operational Disruption: OT processes require real-time communication, and strict security controls can introduce latency or interruptions older hardware cannot make up for.
- Limited Security Resources: OT teams may lack cybersecurity expertise, making it difficult to implement and manage Zero Trust frameworks.
- Cost of Implementation: Upgrading legacy systems and deploying security solutions tailored for Zero Trust can require significant investment.
- Interoperability Concerns: Many OT environments feature equipment from different vendors with varying security capabilities, making a standardized Zero Trust approach more challenging.
Zero Trust is A Team Effort
OT admins can’t do it alone. Even with a deep understanding of their building systems and network topologies, they’ll still need help from IT teams or external security experts to build an effective zero trust architecture.
That’s because zero trust involves more than device-level visibility or blocking unauthorized BACnet traffic. It requires coordinated efforts across authentication protocols, identity management, traffic segmentation, and real-time monitoring—areas where IT typically has more experience and infrastructure in place. For OT teams used to managing static, isolated networks, this shift toward integrated, identity-based access controls is a major transition.
Whether it’s your in-house IT department or a trusted consultant, collaboration in projects and training—like bringing in security expertise—is a smart move. Here’s why:
- Identity and access management (IAM): IT can help define user roles and implement identity-based access controls, which are foundational to zero trust.
- Network segmentation: IT teams understand how to break the network into secure zones without disrupting communication between critical systems. But OT expertise is still required. Think VLANs and BBMDs.
- Threat detection and response: IT teams are equipped with advanced tools to monitor and respond to possible cyber threats in real time.
- Integration with existing security frameworks: They can help align OT security with broader enterprise security initiatives.
Zero trust can dramatically reduce the risk of unauthorized access and lateral movement within OT networks—but only if it’s implemented thoughtfully. For that, teamwork is key.
Network Visibility is Critical for Zero Trust in OT
A fundamental requirement for Zero Trust is deep network visibility. Organizations cannot secure what they cannot see, making real-time monitoring and analysis essential for effective cybersecurity. Without a clear understanding of the devices, communications, and interactions occurring within an OT network, it is impossible to enforce Zero Trust policies effectively.
Advanced monitoring tools for OT networks like OptigoVN play a crucial role in implementing Zero Trust security. These tools eliminate network blind spots, enabling deep packet inspection of BACnet traffic, and allow teams to identify potential vulnerabilities and unauthorized communications before a breach occurs. Here’s just a partial list of how OptigoVN can help you create the right environment for Zero Trust security to be the most effective.
| Zero Trust Challenge in OT Networks | How OptigoVN Helps |
|---|---|
| You Can’t Protect What You Can’t See Many OT networks lack visibility into connected devices, unauthorized communications, or misconfigured assets. | Real-Time Device Mapping OptigoVN provides a complete, real-time view of all connected OT devices, identifying unauthorized connections and misconfigurations. |
| Real-Time Monitoring A Zero Trust strategy requires continuous monitoring of network traffic, device behavior, and authentication requests. | Live Traffic Analysis OptigoVN continuously monitors BACnet traffic, providing live insights into device activity and potential security violations. |
Anomaly Detection & Threat Response Deep network visibility allows security teams to spot suspicious activity early and take action before it escalates. | Packet Inspection & Diagnostics OptigoVN detects unusual BACnet traffic patterns, rogue devices, and unauthorized commands to enable fast threat response. |
| Segmentation Enforcement OT environments often have flat networks—network monitoring solutions help enforce micro segmentation to protect critical systems. | VLAN & BBMD Visibility OptigoVN highlights cross-segment traffic, helps enforce VLANs, and ensures BBMDs are properly configured to limit unnecessary communication. |
| Granular Visibility and Control Granular visibility is needed to effectively implement and enforce Zero Trust principles in OT networks. | Deep Site-Specific Visibility Site Scopes provide remote, real-time access to device behavior, BACnet traffic, and security gaps, supporting proactive security enforcement. |
With Optigo Visual Networks, client OT network monitoring and troubleshooting just got easier. To find out for yourself, click here to request a demo, or create your free account and start exploring today.
FAQ: Zero Trust Security in OT Networks
- What is Zero Trust security in OT networks?
Zero Trust security is a cybersecurity framework based on the principle of “never trust, always verify.” In OT networks, it means that every device, user, and connection must be continuously authenticated and authorized—no matter where it originates. - Why is Zero Trust important for OT networks?
As OT networks become more connected to IT systems and the internet, traditional perimeter-based security is no longer enough. Zero Trust reduces the risk of unauthorized access, lateral movement of threats, and operational disruption by enforcing strict access controls and network segmentation. - How does Zero Trust reduce risk in OT environments?
Zero Trust minimizes risk by blocking unauthorized users and devices, limiting what approved users can access, and monitoring traffic in real time to detect suspicious behavior before it spreads across the network. - What challenges come with implementing Zero Trust in OT?
Some common challenges include legacy systems that weren’t designed with modern security in mind, limited in-house cybersecurity expertise, interoperability issues, and the potential for operational disruptions if Zero Trust is poorly implemented. - Do I need both IT and OT teams to implement Zero Trust?
Yes. Zero Trust requires collaboration between OT administrators, who understand building systems and network behavior, and IT teams or security consultants, who can manage access controls, segmentation, and threat detection technologies. - How does network visibility support Zero Trust in OT?
You can’t secure what you can’t see. Tools like Optigo Visual Networks provide real-time mapping, live traffic analysis, and BACnet packet inspection—key capabilities for identifying vulnerabilities, enforcing segmentation, and spotting threats early. - Can Zero Trust be applied to legacy OT systems?
Yes, but it requires careful planning. Even if older devices can’t support every modern security measure, Zero Trust strategies like segmentation, network monitoring, and access control can still help reduce exposure and improve security posture. - What role does Optigo Visual Networks play in Zero Trust?
OptigoVN supports Zero Trust by giving OT teams deep, real-time visibility into their networks. It helps identify misconfigurations, track device behavior, enforce VLANs and BBMDs, and detect anomalies before they escalate into full-blown incidents.
FAQs are created with the assistance of generative AI.
