How to Improve Mean-Time-to-Repair (MTTR) and Strengthen OT Cybersecurity

Due to digital transformation, previously disparate information technology (IT) and operational technology (OT) environments have converged — giving rise to cyber-physical systems (CPS). As these systems become increasingly interconnected, simple, secure, and reliable access to operational networks has shifted from a convenience into a necessity. 

However, as connectivity in CPS environments grows to improve business outcomes, organizations have typically turned to traditional access solutions like VPNs and jump-servers. According to Gartner, these approaches have “proven increasingly unsecure and complex to manage. They also often lack the granularity to provide access to a single device, providing access to the entire network instead.”

Due to the unique operational constraints of CPS environments, critical infrastructure organizations require a solution that not only provides seamless access for both first- and third-party users, but also effectively reduces Mean Time to Repair (MTTR).

What is Mean-Time-to-Repair (MTTR)? 

For OT engineers, MTTR is the average amount of time it takes to complete a repair or other necessary maintenance task on an industrial asset — from the moment at which the engineer connects to the asset and initiates the repair, to the moment at which they finalize the repair and disconnect from the asset. Generally speaking, the longer the MTTR, the worse the consequences of both diagnosed and undiagnosed maintenance issues are likely to be. This tends to be especially true when such issues pertain to critical vulnerabilities, dangerous configuration errors, or anything else that poses a considerable threat to OT availability, integrity, and/or safety.

MTTR is also an important metric for the security leader — typically the CISO — responsible and accountable for ensuring the entire network – IT and OT environments – is up and running as it should be. The lower the MTTR, the less risk of downtime and disruption to operations and business performance.

Calculate MTTR 

Mean-time-to-repair is calculated with a simple formula that divides total maintenance time by the number of repairs.

Although this calculator can give you an estimate of your MTTR, not all outages are equal. That’s because the nature and depth of problems can vary in complexity. Some systems and equipment may take longer to repair due to unique specifications, or may go down during peak hours, which can be more costly.

Variables Impacting MTTR

There are seemingly countless variables that can impact MTTR, but user experience is arguably one of the most impactful for remote OT engineers who rely on remote access solutions. When a solution's user experience is neither frictionless nor reliable, the OT engineers who use it are forced to contend with challenging conditions that can increase MTTR and the exposure to risks associated with it. Some other notable variables include:

• Detection & Diagnosis: Without comprehensive asset visibility, advanced monitoring systems, or diagnostic tools, organizations may find it difficult to monitor components and detect failures quickly. This can lead to reduced troubleshooting time. 

• Tool & Resource Availability: Advanced systems may require specific tools or skill levels to effectively remediate the issue. If an organization does not have the proper tools or resources to perform a repair, they can see a significant impact on MTTR. 

• Regulatory Constraints: In several industries, repairs may need to comply with regulatory standards, the time taken to ensure compliance is met could impact MTTR. 

Understanding the most critical variables impacting MTTR can help organizations to implement strategies, tools, and best practices to optimize the repair process and improve MTTR. Here's a few to get you started. 

How to Improve MTTR 

1. Establish a comprehensive asset inventory: 

In order to improve MTTR organizations must be able to access their systems quickly and efficiently; however, without a comprehensive asset inventory, this can be a near impossible task. By maintaining a real-time status of all assets in your environment — including location, status, how they are utilized, and how they interact with each other — organizations can detect failures quickly, prevent unexpected downtime, improve decision making when it comes to repairs, and allocate resources efficiently. All of which helps to significantly improve MTTR.  

2. Effective network segmentation techniques:

Network segmentation is particularly important in improving MTTR as it allows organizations to simplify the process of managing, monitoring, and repairing their networks. By restricting lateral movement through the network, successful segmentation can isolate problems and allow them to be diagnosed and repaired quickly. It also allows for faster troubleshooting, effective maintenance, and better monitoring. In order to better inform network segmentation, organizations can implement the Purdue Model. The Purdue Model depicts best practices for segmenting the IT network (Levels 4 and 5) from the OT environment (Levels 0-3). By improving network security, streamlining processes, and enhancing the reliability in OT networks, the Purdue Model can aid in the reduction of MTTR. 

3. Continuous threat detection: 

Effective threat detection plays a critical role in improving MTTR as it helps organizations to identify anomalies and potentially hazardous events before they escalate. With the use of multiple detection engines, organizations can profile all assets, communications, and processes to generate a behavioral baseline that characterizes legitimate traffic to weed out falses positives. This allows for rapid response once a threat is detected and prevents recurrence of the same or similar threats. 

4. Implement a secure access solution: 

The most effective way to improve MTTR is to implement a secure remote access solution that is purpose-built for the unique constraints of a CPS environment. The right solution effectively reduces MTTR by facilitating quicker issue resolution, operating under low bandwidth conditions, ensuring high system availability, and upholding critical site survivability — all while ensuring that critical systems remain both operational and secure. 

Claroty xDome Secure Access does just this by making it faster and easier for OT engineers to safely connect to and troubleshoot assets at any time, from anywhere, and address exploitable flaws that could lead to process interruption or manipulation.

To learn more about how Claroty xDome Secure Access effectively reduces MTTR and boosts uptime, request a demo.