Protect Critical Operations with OT Network Segmentation

As aspects of the business world that were once independent from one another have become increasingly interconnected, the convergence of Operational Technology (OT) and Information Technology (IT) has led to unprecedented efficiencies. It’s also created novel security challenges that create significant risk for organizations, including production delays and supply chain disruption. Without proper safeguards, these interconnected systems become highly vulnerable to cyberattacks that can cascade across both IT and OT environments, amplifying the potential damage. OT network segmentation is the key to reducing these risks and protecting against the growing and ever-evolving array of cyber threats that target industrial control systems (ICS), manufacturing plants, energy grids, and other critical infrastructure operations. 

Why OT Network Segmentation is Best Practice 

Traditional OT environments were isolated, air-gapped systems designed for safety, reliability, and real-time operations. However, as these systems have become integrated with broader IT networks, they have inherited vulnerabilities that make them prime targets for cyberattacks. Without effective segmentation, a single compromised device can allow attackers to traverse your entire OT network, potentially shutting down essential processes, causing physical damage, and jeopardizing safety. 

Numerous examples show how failure to segment OT networks properly can lead to catastrophic consequences. 

• Clorox was targeted by an August 2023 cyberattack that shut down production and limited supplies, leading to a $49M loss. Inadequate network segmentation may have played a role in the severity of the incident.  

• In May 2021, Colonial Pipeline, one of the largest fuel pipelines in the United States, suffered a ransomware attack. The DarkSide ransomware group infiltrated the company’s IT systems, which led to a precautionary shutdown of OT systems that control the pipeline. The shutdown caused widespread fuel shortages across the Eastern United States, leading to panic buying and significant disruptions to fuel supply.  

• Due to poor security, a hacker gained access to the Oldsmar, Florida water treatment plant in 2021, then attempted to increase the levels of sodium hydroxide (lye) in the water supply to dangerous levels by manipulating the plant’s OT systems. The malicious changes were quickly noticed and reversed by an alert operator, but the breach underscored the vulnerability of critical infrastructure, particularly in smaller municipalities. 

• Norsk Hydro, a major aluminum producer with significant operations in the U.S., was hit by the LockerGoga ransomware in 2019, disrupting both IT and OT systems across the company’s global network. The attack led to widespread operational disruptions, forcing many of Norsk Hydro’s plants to revert to manual operations. The financial impact of the attack was significant, with an estimated loss of over $70M. 

• In 2017, a petrochemical explosion was narrowly averted after Triton malware gained access to Schneider Electric safety equipment in the ICS at a plant in Saudi Arabia. 

Each of these incidents reveal how vulnerable systems can be when they are not properly hardened. OT network segmentation is the solution that ensures security and keeps critical systems safe. By offering multiple layers of protection and dividing the network into smaller, isolated segments, organizations can: 

• Limit Lateral Movement: Segmentation confines potential breaches to a single segment of an OT system, preventing attackers from moving freely across the network. 

• Enhance Transparency and Control: Security teams gain better visibility into each segment, enabling them to monitor traffic more effectively and detect anomalies quickly. 

• Reduce Attack Surfaces: It becomes more difficult for attackers to access high-value targets when critical systems are isolated and the overall potential attack surface is minimized. 

• Improve Compliance: Many regulatory frameworks require strict control over network access, and segmentation helps organizations meet these requirements by ensuring that only authorized devices and users can access sensitive segments. 

These benefits not only protect complex systems against external threats but also mitigate risks from insider threats, whether intentional or accidental.  

Six Steps to OT Network Segmentation 

Effective OT network segmentation requires a strategic approach that aligns with both the organization’s operational goals and security requirements. Security officers should take these essential steps to implement a robust OT network segmentation strategy that will reduce the risk of cyberattacks on their networks and ensure that critical infrastructure remains secure: 

1. Identify Assets: Begin by conducting a comprehensive inventory of all OT assets. Identify their communication patterns, dependencies, and security requirements. This step is especially important for legacy systems that may need updating to support modern security protocols. 
2. Define Security Zones and Conduits: Use the Purdue Enterprise Reference Architecture (PERA) or the IEC 62443 standards to define zones and conduits. Zones should group assets with similar security needs, while conduits control the flow of information between these zones. Ensure that all data entering or leaving a zone is tightly controlled. 
3. Develop and Implement Security Policies: Clarify how data can move between zones with clear policies enforced by firewalls or other security devices that act as gatekeepers to ensure that only authorized traffic is allowed. 
4. Implement Microsegmentation for Additional Protection: To further boost security, divide zones into smaller segments based on granular security requirements. Device microsegmentation prevents unauthorized lateral movement within a zone, adding an extra layer of defense. 
5. Continuously Monitor: OT environments are dynamic, with frequent changes in devices and processes. Continuous review is essential to keep segmentation policies enforced and promptly address any deviations. Regular assessments and updates to the segmentation strategy are necessary to accommodate new threats and technologies. 
6. Share Responsibility Among Teams: OT, IT, and security teams should collaborate closely, keeping each department’s challenges and priorities in mind. Conduct regular training sessions to keep all staff members up to date on best practices and emerging threats. 

Secure the Future of Your OT Network 

As OT and IT environments continue to converge, the need for OT network segmentation becomes increasingly evident. Robust segmentation preserves operational continuity by ensuring the safety, reliability, and resilience of your entire network ecosystem. It’s a best-practice approach that prevents unauthorized access and protects critical infrastructure from both internal and external threats.  

TrueFort offers advanced solutions tailored to the unique challenges of OT environments. Request a demo with our experts to learn more about how our platform can help you achieve comprehensive network security.