There are major changes occurring in Operational Technology (OT) ecosystems. In the past, industrial control systems, manufacturing plants, power grids, and other critical infrastructure stayed separate. They were kept apart from business IT systems and the Internet. However, today’s increasing connectivity allows industrial systems to perform automated processes, work remotely, and receive real-time analysis.

As these OT environments become more connected, cyber criminals notice their weak points. OT environments are now targets for threats like ransomware, supply chain attacks, and nation-state attacks. One solution getting serious attention is using Zero Trust for OT Networks.

The Growing Security Challenge in OT Environments

In OT security, traditional models have always been centered on the idea that whatever was within the network environment could be trusted completely. Security mainly revolved around perimeter defense, and firewalls were the best form of security available.

This model will no longer suffice.

Modern OTs typically consist of remote contractors, outside vendors, cloud-based apps, and converged IT/OT environments. One breach, whether through a compromised machine or credentials, can allow an attacker to gain access to essential systems.

While IT attacks only affect operations, attacks on OT systems can stop production. They can also damage equipment, disrupt public services, or create safety risks. Therefore, there needs to be a new security model that assumes threats from everywhere.

What Does Zero Trust Mean for OT Networks?

The core principle of Zero Trust is simple: never trust, always verify.

Rather than automatically trusting users, devices, and applications based on the fact that they are within the network boundary, every access attempt will need to be continually verified and authenticated.

The practice of Zero Trust for OT Networks includes the following:

• Identity verification of users prior to granting access.
• Granting access privileges based on job function.
• Monitoring of the network traffic.
• Network segmentation.
• Verification of the security of devices prior to allowing access.

It does not mean that the network is devoid of trust, rather it means the network earns trust through constant verification.

Why Traditional Security Models Fall Short

A lot of industries are using old security measures that have been put in place many years ago. They may lack the most modern means of authentication and were not designed with the intention of linking to the outside world.

The hackers know all these shortcomings. After gaining access, they usually hop from one computer to another to find valuable resources and elevate their privileges.

The zero trust model makes sure that there is an additional layer of security placed everywhere. If any of the accounts or devices has been breached, then further actions will be hindered.

Key Benefits of Zero Trust for OT Networks

• Reduced Attack Surface: With strict access controls and network segmentation in place, the attack surface will be dramatically reduced.
• Enhanced Visibility: Zero Trust requires constant monitoring and verification of any activity taking place inside the organization. It enables better visibility of any activities performed by users and any suspicious behaviors observed within the system.
• Reduced Risk from Insider Threats: The attack can arise from external factors, but it may arise from internal factors too. Misconfiguration of credentials, phishing, and other kinds of attacks can be problematic when it comes to accessing accounts. Limiting the access can help prevent many of these threats.
• Faster Incident Response: If there is a threat, it will not affect many other aspects of the network as it would spread in an unsegmented network. This reduces the effort required to pinpoint the issue and take action.
• Steps to Create Zero Trust: Adopting Zero Trust in your industrial network does not require changing everything immediately.

First, the company needs to determine what its essential assets are and how systems communicate. After this is accomplished, technologies and policies can be introduced one by one.

Security departments should consider increasing their visibility capabilities in both the IT and OT segments. Detection technologies monitoring the flow of information can be used to recognize threats early on.

Looking Ahead

With increased connectivity within the OT environment, cyberattacks pose increasing levels of risk to companies. Relying exclusively on perimeter-based security will no longer cut it when trying to secure critical operations in an increasingly digital world.

Zero Trust Security for OT Networks provides a safer framework by starting with the assumption that nothing and nobody should be trusted. By leveraging continuous validation, least privilege, and increased visibility, companies can better defend against internal as well as external attacks.

At a time when operational resilience and cybersecurity go hand in hand, the adoption of Zero Trust principles cannot remain an option anymore.