Strategies to Address Challenges in Securing Legacy OT Systems

Securing legacy OT systems poses significant challenges as these ageing systems lack modern cybersecurity features. Organisations may overcome these difficulties by implementing strategies that strike a compromise between improved security and the constraints of the current infrastructure. As we spoke about challenges in securing legacy OT systems in our previous article, here are some strategies to address these challenges we have seen in securing legacy OT systems:

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1.????Performing risk assessments include locating, assessing, and ranking both the threats to legacy OT systems and the systems criticality to operations. Organisations may create and put into effect plans to reduce those risks and enhance system security. Regular risk analyses assist in proactive vulnerability management and security enhancement.

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2.????System hardening for old OT systems entails putting security measures in place, such as firewalls and access restrictions, as well as removing unused services and vulnerable protocols. Hardening reduces the attack surface and improves security, and is vital to minimise unforeseen consequences.

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3.????Implementing data backups and recovery plans involves regularly backing up critical data, testing procedures and monitoring status. Data recovery is made possible in the event of loss or corruption through secure storage and frequent testing. Having redundant backup systems adds an additional degree of security.

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4.????Plans for disaster recovery are essential for protecting OT systems that handle vital corporate and production processes to ensure continuity and lessen the effects of interruptions. Organisations may create a strategy and set procedures to identify crucial data and systems and restore them in the event of a catastrophe.

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5.????Regular updates and patching are crucial for maintaining the security of legacy OT systems: these systems are susceptible to attacks because, typically, they were not designed with security in mind. It is crucial to implement a patch management programme that includes frequent reviews, and testing and monitoring of change. Equally, it is essential to make sure that manufacturers and suppliers keep providing security updates and to have a strategy in place for dealing with security problems.?Where systems are ‘'out of support', additional hardening and protection must be employed (see 2 above).

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6.????Network segmentation lowers the attack surface and limits the spread of a cyberattack by splitting a network into isolated zones. Should there be a successful attack on an OT system, segmentation separates crucial assets and functions and reduces damage. Segregation, on the other hand, works within a network segment to control who and what has access to the systems therein. Critical assets should be identified, systems with comparable security requirements should be grouped, and segmentation and segregation strategies should be reviewed constantly. CyberPrism ’s ProcessGuardTM system is specifically designed to be embedded safely in OT networks, and provides advanced segmentation and segregation whilst allowing vital industrial processes to continue during an attack.

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7.????Implementing security awareness and training significantly reduces the risk of cyberattacks being successful in legacy OT systems due to human error. Clear incident reporting procedures, frequent awareness workshops, and basic cybersecurity training should all be routine and a culture in which people report early promoted (potentially even rewarded). To respond to risks that change over time, there must be constant evaluation and updating.

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As many OT systems are legacy and consequently ‘Out of support’, legacy OT systems are difficult to secure. Nevertheless, focusing on techniques like risk analyses, system hardening, data backups, disaster recovery plans, routine upgrades, network segmentation, and security awareness training may improve security and safeguard crucial infrastructure. By managing risk appropriately, we ensure that legacy OT systems are sufficiently resilient.?