Graphic showing an operational technology (OT) network with various industrial assets and connected systems, highlighting vulnerabilities and risks. Arrows point to weak points where exposure to cyber threats occurs, emphasizing the need for OT Exposure Management to secure critical infrastructure.

Mastering OT Patch Management for Enhanced Cybersecurity

Operational technology (OT) patch management refers to applying updates, fixes, and enhancements to the software and firmware running on devices and systems in industrial and critical infrastructure environments. Unlike the traditional IT world, OT systems are unique in their purpose and are primarily intended to control and monitor physical OT systems are unique in their purpose and are primarily intended to control and monitor physical processes. Therefore, OT patch management focuses on ensuring the security, reliability, and functionality of software that controls these processes.

The importance of OT patch management cannot be overstated, especially when it comes to safeguarding critical infrastructures. OT systems are the backbone of industries such as energy, manufacturing, transportation, and healthcare. Any compromise can lead to severe consequences, including disruptions in operations, safety hazards, and economic losses. Effective OT patch management is essential for mitigating vulnerabilities, reducing the risk of cyberattacks, and ensuring the continuous and secure operation of critical infrastructures.

This article highlights the vital role OT patch management plays in ensuring the security and reliability of your critical infrastructure.

OT Patch Management Challenges 

Mastering OT patch management comes with its own set of challenges. Unlike the IT realm, OT environments often have diverse and complex systems that require specialized handling. The following challenges are particularly prominent:

OT diversity 

OT environments are characterized by a wide range of systems and devices. These include industrial control systems (ICS), programmable logic controllers (PLCs), remote terminal units (RTUs), and human-machine interfaces (HMIs), among others. Each component can come from a disparate vendor and might present a unique operating system and software dependencies. Managing patches across such diverse environments requires a nuanced approach.

Forming the backbone of many OT environments, ICS often comes from multiple vendors. This adds complexity to OT patch management, as they might release patches on irregular schedules. In addition, compatibility issues can arise when applying patches across various ICS components. Coordinating with multiple vendors for patch approvals and ensuring seamless integration poses a significant challenge.

Compatibility and approval issues 

Implementing operating system patches in an OT environment isn’t as straightforward as in traditional IT settings. Many OT systems rely on legacy operating systems that might no longer receive official support or updates from vendors. Introducing new patches to such systems can lead to compatibility issues and unintended consequences, adding to the update challenge.

Before applying any patch, your OT team often needs to obtain approval from hardware vendors. This ensures that the proposed patch doesn’t adversely affect equipment functionality. Additionally, compatibility checks are essential to verify the patch is suitable for the specific software version running on the OT devices.

 

Risk Assessment and Prioritization

A proactive and risk-based approach is essential to addressing such OT patch management challenges. Risk assessment and prioritization play critical roles in ensuring that patches are deployed efficiently and effectively.

Criticality assessment of OT assets 

The first step in risk assessment is assigning criticality scores to OT assets. Here, you evaluate the business impact of a potential compromise on each asset. Those deemed critical, for which a compromise would have severe consequences, should be prioritized for patching.

In addition to the business impact, maintenance and replacement costs should also be factored into your assessment. Some assets could be costly to maintain or replace, making them more critical in relation to overall risk. Understanding these factors helps in determining the priority of patch deployment.

Seeking new patches and OT vulnerabilities 

Staying informed about patches is a continuous effort. Your OT team is able to promptly address potential threats only by staying informed about the latest vulnerabilities and available patches. They should actively seek patches rather than waiting for vendors to push updates. 

Subscribing to vendor newsletters, security advisories, and mailing lists from both vendors and cybersecurity organizations can provide timely notifications about new patches. Participating in vulnerability disclosure programs, collaborating with industry peers, and leveraging threat intelligence sources are essential.

Timely awareness enables your organization to assess the impact on systems and plan for patch deployment accordingly. By staying ahead of the curve, your organization can reduce the window of vulnerability and enhance overall cybersecurity.

See Protecting Critical Infrastructure with OT Risk Management to learn more. 

 

Best Practices in OT Patch Management

To navigate the challenges and implement effective OT patch management, your organization should adopt a set of best practices that encompass the entire patch management lifecycle.

OT asset inventory 

Your OT team should have a clear, thorough understanding of all OT devices, systems, and software present. Maintaining a comprehensive and evergreen asset inventory serves as the basis for assessing vulnerabilities, determining criticality, and planning patch deployments.

Given the complexity of OT environments, manual inventory management is often impractical. Automated tools such as OTORIO Titan can help your organization maintain an up-to-date inventory by continuously scanning your network, identifying devices, and tracking software versions. Such tools streamline patch management by providing accurate, real-time OT environment information.

Assigning criticality to OT assets 

Assigning criticality scores involves developing a clear and consistent methodology. This could include creating a scoring system that considers factors such as business impact, safety implications, and operational dependencies. Establishing a transparent process for assigning criticality scores ensures that patch deployment prioritization aligns with organizational goals and risk tolerance.

But criticality assessment shouldn’t be solely based on the potential for cyber threats. It should also consider the broader impact on business operations, safety, and the financial implications of maintaining or replacing assets. Taking a holistic view lets your organization make informed decisions about the priority of patching specific assets.

Prioritize patch deployment 

In large and complex OT environments, simultaneous patch deployment across all assets might not be feasible. Challenges such as system dependencies, operational constraints, and potential downtime must be considered. Prioritization becomes essential to ensure that critical vulnerabilities are promptly addressed.

Effective prioritization involves considering both the criticality of assets and the associated risks. High-criticality assets with known vulnerabilities should be addressed first to minimize the risk of exploitation. To prioritize patch deployment effectively, you should strike a balance between urgency and operational considerations.

Assess and reduce risk for exempted patches 

In some cases, patches might be deemed uninstallable due to technical or operational reasons. In such situations, your OT team should implement alternative controls to mitigate the risk associated with unpatched vulnerabilities. These might include enhancing boundary protection, implementing network segmentation, and intensifying monitoring to detect and respond to potential threats.

While patches present a critical cybersecurity element, they’re not your only line of defense. Strengthening boundary protection through firewalls, implementing network segmentation to isolate critical assets, and enhancing monitoring capabilities contribute to a comprehensive risk reduction strategy. Such measures provide additional layers of defense, especially when immediate patch deployment isn’t feasible.

Aligning patch management with change management standards 

Integrating patching into your broader change management process ensures a systematic and controlled approach to updates. Following established change management standards helps your organization assess the impact of patches on OT systems, plan for contingencies, and maintain a record of changes for audit purposes.

The following are integral steps for effective OT patch management:

✔ Create a baseline configuration for OT systems

✔ Record all changes on an ongoing basis

✔ Regularly review your OT configuration against security standards

✔ Document the patch deployment process

In addition, having a rollback plan ensures that in the event of unexpected issues, your organization can revert to a previous state while minimizing disruptions.

Document your patch management policy 

A comprehensive patch management policy serves as a roadmap for navigating OT environment complexities. Your policy should outline procedures for vulnerability assessment, patch deployment, risk assessment, and ongoing monitoring. It should also provide guidelines for communication, collaboration with vendors, and continuous patch management process improvement.

Several industry standards and frameworks provide guidelines for developing patch management policies. Refer to IEC 62443, NIST SP 800-82, and ISO/IEC 27001 for best practices and recommendations. Tailoring these standards to the specific requirements of your environment ensures a robust and compliant OT patch management policy.

 

Conclusion

Mastering OT patch management is essential for enhancing cybersecurity in critical infrastructures. The challenges associated with diverse OT environments, compatibility issues, and the need for vendor approvals require a strategic and proactive approach. By conducting risk assessments, prioritizing patch deployment, and adopting best practices, your organization can effectively safeguard its OT systems.

Achieving a balance between security needs and practical implementation is key to navigating the complexities of OT environments and staying ahead of evolving cyber threats. As your organization continues to rely on OT systems for essential operations, investing in robust patch management practices becomes an imperative aspect of your overall cybersecurity strategy. Click here to learn more.