How to Protect Your OT Systems from Cyber Threats: A Comprehensive Cybersecurity Guide

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Written By Charlotte Miller

As digital transformation accelerates, IT and operational technology systems are converging rapidly. But this integration also expands the attack surface for cyber threats. A holistic approach to securing OT environments is essential for risk mitigation. This guide will cover the best practices for protecting your critical OT assets.

The Convergence of IT and OT Systems

OT systems like SCADA and ICS operate on isolated networks. That’s due to their unique reliability and real-time demands. However, the Industrial Internet of Things (IIoT) is now powering connectivity and data integration between IT and OT stacks.

While this convergence enables efficiency and insights, it also introduces cyber risks. These risks would require you to resolve them as soon as possible. Some key challenges include:

  • Legacy OT devices often lack modern security capabilities.
  • Visibility is limited to assets, vulnerabilities, and threats across converged networks.
  • Monitoring siloed IT and OT systems strain security resources.
  • Patching and upgrades can disrupt sensitive OT processes.

The Rise of Connected Industrial Systems

As digital technology evolves, we need to understand modern IT/OT convergence. In the early days of control systems, OT solutions were air-gapped systems. They have little to no connection to external networks. Concerns regarding cyber vulnerabilities were low during that time.

As a result, OT architectures and network protocols have diverged from IT environments for enterprises. Proprietary technology stacks are siloed from corporate systems. These stacks also prioritized uptime over security practices. Two notable practices are authentication and encryption. You must take note that air-gapped OT networks have limitations in visibility and management.

After that, the advent of Ethernet and IP networking allowed OT systems to be interlinked across facilities. It did open the doors for better efficiency through remote control and monitoring. However, it also opened avenues for cyber intrusion. The lack of segmentation ends up enabling lateral threat movement. The need for a cybersecurity guide suddenly rises at this point.

Legacy OT devices and software don’t have modern security capabilities in mind. As a result, they are vulnerable to cyber threats. Attackers can then enter business systems and disrupt operations. The damage they can inflict varies, but it will hinder proper operations.

To give you an example of threats – TRITON and Industroyer have shown their capability to damage key assets. Aside from these threats, additional challenges include the following:

  • Lack of asset inventory and vulnerable legacy devices
  • Unpatched software and operating systems
  • Unsecured remote access channels
  • Poor network segmentation and perimeter controls
  • Minimal security monitoring and response capabilities

In order to secure key OT assets, organizations must use converged governance and control. At the same time, they must account for the unique reliability and safety of every process. As OT environments become more linked to IT systems, security becomes a necessity for both.

Building a Resilient Converged IT/OT Architecture

The ideal converged architecture balances connectivity and security. The key principles you must take note of include the following:

  • Network segmentation. Logically separate OT systems into zones using firewalls. Limit lateral movement of threats.
  • Access controls. Allow only authorized connections between IT and OT based on least privilege principles.
  • OT security monitoring. Detect threats and anomalies in OT traffic using specialized analytics.
  • Updated legacy systems. Replace outdated devices lacking security capabilities when possible.
  • Secure remote access. Employ VPNs, multi-factor authentication, and session controls.
  • Incident response plans. Have playbooks to isolate and contain threats across IT/OT.

Asset Discovery and Management

Gaining unified visibility into all assets across converged IT/OT infrastructure is crucial. Potential discovery methods include the following:

  • Physical audits – Map inventory of devices, applications, and connectivity.
  • Passive monitoring – Capture traffic patterns and analyze for unauthorized activity.
  • Active scanning – Run network scans to identify assets, without impacting availability.
  • Additive data sources – Pull asset data from ERP systems, change logs, and CMDBs.

You’ll also need to maintain an updated central asset inventory. This inventory will contain details like device types, locations, and ownership. Through this, you can facilitate better monitoring, access control, and vulnerability management. Take note that if you’re a company that’s ahead in convergence, the incremental value could exceed $100 million. Prioritizing asset discovery lays the groundwork for realizing this potential.

Intelligently Prioritizing and Deploying Patches

Patching vulnerabilities is vital for system security. However, careless updates in OT environments can disrupt critical processes. Organizations must balance security and availability when patching converged systems.

 A structured approach involves the following:

  • Risk analysis – Evaluate vulnerability severity using CVSS 3.0 framework.
  • Potential impact – Determine the effects of patching on system stability and processes.
  • Change control – Follow a formal change management process.
  • Isolation options – Temporarily isolate systems during patching if required.
  • Backouts – Roll back improperly validated patches causing issues.

Calculate risk vs. benefit, test extensively, and patch during maintenance windows. This balances security and availability.

Managing Evolving Risks Throughout the OT System Lifecycle

With rapidly evolving technology, continuous risk management is imperative to maintain your OT assets. You must conduct the following to your OT systems:

  • Refresh risk assessments – Re-evaluate after changes and periodically.
  • Update vulnerabilities – Monitor advisories and remediate.
  • Review access controls – Add or revoke based on personnel changes.
  • Tune detection rules – Refine algorithms to match new attack methods.
  • Sustain employee education – Refresh training to address emerging social engineering techniques.
  • Maintain drills – Regularly exercise and refine incident response plans.

Identifying and securing both new and existing vulnerabilities is key for resilient operations. You won’t have to worry too much about downtimes caused by attacks.

Comparison Between IT and OT Cybersecurity Postures


IT Systems

OT Systems


Wired and wireless networks, open connectivity

Closed environments historically, now trending towards convergence

Access Control

Role-based access, multi-factor authentication

Limited access, physical controls and conduits


Host/endpoint monitoring, anomaly detection

Passive tapping, controller traffic inspection

Incident Response

Virtualization enables isolation and recovery

Prioritize availability, err on the side of caution

Security Culture

Regular training on cyber risks and response

Limited awareness of cyber threats and impacts

Frequently Asked Questions

1. How can organizations sustain continuous threat protection as IT and OT converge?

Adopt security by design principles for all new implementations. Perform regular risk assessments, access reviews, and training. Check threats across converged networks. Develop integrated response plans. These plans must cover both IT and OT. Maintain robust backups and recovery capabilities.

2. What are some best practices for asset discovery and management?

Maintain a frequently updated centralized inventory of authorized assets with ownership details. Perform both active scanning and passive monitoring to detect rogue devices. Integrate data from CMDBs, change logs, and ERP systems for enhanced visibility. Enforce asset management through controls like network segmentation.

3. How can patching be streamlined to balance risk and operational continuity?

Analyze threats using frameworks like CVSS 3.0 to intelligently prioritize. You also need to study the patches thoroughly before deploying them. Follow change management procedures with rollback provisions. Use maintenance windows and isolation options strategically to limit disruptions.

Defend your OT Key Assets from Cyber Threats

As industrial environments transform, cybersecurity must also evolve to deal with new threats. You must converge both IT and OT systems to maximize security. But this requires you to integrate security into the foundation. Practices such as asset visibility, access controls the like can help you reach that security goal.

You will also need to adopt the best practices for cybersecurity to amplify security. At the same time, you are minimizing the system’s vulnerability. At first, this task can be daunting but it will be rewarding for your organization. That’s because a good cybersecurity guide ensures your assets are protected for years to come.