Eight Ways Firewalls Enable Zero Trust within OT and Industrial Networks

In OT security: Securing the operational tech environment. And this is not only about the antioxidants in the new kind of electromagnetic waves — those networks that run our industrial activity and their disruption leads to major headaches, or even a dangerous situation. Industrial firewalls are what can help you there. They reinforce the Zero Trust model, providing powerful security for an environment that has traditionally left much to be desired in terms of IT security.

In this blog, we are going to break down a few of these key concepts and how firewalls help implement Zero Trust in OT networks.

1. OT Security Challenges

So, let’s admit it — OT environments are different than your average corporate IT network. They have unique challenges:

• Legacy systems: Numerous OT devices are old and were not designed to be secured.
• Poor patching: Downtime represents lost production so you tend to avoid updates that require system restarts.
• OT Devices Are Using Different Communication Protocols: Unlike IT, OT devices use protocols that are not typically seen in IT.
• High impact risk: A cyberattack here can halt machinery, injure workers or cause environmental harm.
• Lack of visibility: Difficult to analyze all devices or traffic flows in real-time.

Due to these challenges, OT networks cannot solely depend on perimeter defenses as they do in IT networks. You need a more granular, proactive approach.

2. Micro-Segmentation in OT

Network segmentation is one of the best methods to protect OT systems. Not just a segmentation, mind you — but a micro-segmentation done via industrial firewalls.

Micro-segmentation is the practice of dividing the OT network into small zones or segments. And instead of one huge open network that everything talks freely on, you build walls. Firewalls dictate what can flow through between these segments. This greatly reduces the attack surface.

Why is this important?

• Split up breaches: Even if one zone is breached, attackers can’t just hop around like they could on a traditional network.
• Improved control: You determine specifically who or what communicates with each device or group.
• Custom rules: You customize firewall policies to specific OT protocols and devices.

This may include isolating control systems from safety systems and diagnostic devices from process machinery. This level of fine-grained control is enabled by industrial firewalls.

3. Restricting Lateral Movement

In OT networks, hackers often gain access by breaking through the weakest link. Next, they move sideways, a process known as lateral movement, to penetrate deeper into mission-critical systems. This is especially perilous since once inside, attackers can cripple operations or inflict physical damage.

Firewalls prevent this lateral movement in the following ways:

• Segmentation with very strict access controls
• Deep packet inspection for OT-specific traffic awareness.
• Preventing unauthorized protocols, or devices, from being able to communicate.

That way, if hackers breach the outer defenses, they encounter several firewall checkpoints along the way. It’s like having all the doors between every room in a house locked, not just the front entrance.

4. Role-Based Access

Zero Trust means to never trust anyone or thing by default. This is where Role Based Access Control (RBAC) comes into play. Firewalls implement RBAC by determining who or what is permitted to communicate with which sections of the OT network.

This means:

• Users receive only the least access necessary, nothing additional.
• Machines communicate only with allowed devices.
• It is easy to give and revoke temporary access.

By implementing RBAC within your industrial firewalls, you can provide a method for ensuring that mistakes or malicious access do not propagate further and.

5. Real-Time Monitoring

Setting firewall rules is just the beginning of the job. You have to monitor the network traffic in real-time. Real-time monitoring also enables the organization to flag news suspicious activity quickly, which is a critical factor for OT where seconds count.

Firewalls designed for OT security can:

This includes:

• Real-time Traffic Flow analysis, and so on
• Default on anomalies — to unexpected protocols that don’t physically follow standards or unusual communications on the device.
• Interaction with the Security Information and Event Management (SIEM) tools for extended analysis.

The sooner you respond to these alerts, the less damage they can do to your OT environment, placing it back under your control.

Summary

In summary, an industrial firewall is an important tool to enable Zero Trust in OT and industrial networks. They support network segmentation via micro-segmentation, limit lateral movement, implement role-based access, and offer real-time monitoring. All with properly used OT firewalls in place to help mitigate your enterprise risk — if you care about OT security, this should be music to your ears.

Keep in mind that the path to Zero Trust is not a single step — it is a work in progress. Update firewalls, audit access policies periodically and be on the lookout for new threats. Under the right guidance, you can develop a secure, resilient OT environment.

Prioritizing well-planned network segmentation and robust industrial firewalls is a great start to improving your OT security.