From Air-Gapped to Always-On: Securing Legacy OT Systems in Modern Manufacturing By: Pritam Shah, Global Practice Head - OT Security and Data Security, Inspira Enterprise

Prior to the Industry 4.0 era, the Operational Technology (OT) ecosystem had limited cybersecurity risks as they were isolated from external networks and the internet.  During those days, with air-gapped architecture, the chances of cyber attacks were less as the air-gaps created between IT and OT environments acted as digital moats.  It was considered impossible for any data to enter or leave OT environments unless manually done.

Limitations of air-gapping in modern manufacturing

As said, historically, air-gapping was the most prevalent security measure across manufacturing organizations, where the OT system was physically isolated from the unsecured networks to ensure the control systems and sensitive data were secured. Being extremely sensitive, even a minor disruption to OT systems leads to devastating consequences, including financial losses.  Hence, traditionally, manufacturing organizations with OT systems have always isolated OT from IT, creating an air gap.  However, with the acceleration of digital transformation across the manufacturing sector, the legacy OT systems were exposed to the internet and internal networks for remote monitoring and automation, making them no longer secure from cyberattacks.  Manufacturers embracing IT and OT convergence for the several benefits it offers have their OT environments exposed to modern-day cyber threats, uncovering new vulnerabilities.  Air gaps are vulnerable to several attack vectors, such as misconfiguration, insider threats, supply chain vulnerabilities, and others.  OT security incidents are on the rise in the manufacturing industry as IT and OT converge, with cybercriminals targeting manufacturing facilities for financial gain and other reasons.  However, not all manufacturing companies are prepared to combat these attacks with robust security measures, which can result in operational downtime, financial losses, reputational damage, and even safety risks.

A recent global study by Omdia revealed that 80% of manufacturing companies experienced a significant increase in overall security incidents or breaches last year, but only 45% were adequately prepared in their cybersecurity.  Those affected manufacturers reported a resilience or availability issue that cost individual organizations between USD 200,000 and USD 2 million, with the biggest hit when incidents affected enterprise and corporate systems or production control.

Key strategies in security legacy OT systems

In today’s manufacturing environment with always-on hyperconnected OT systems, they are increasingly exposed to cyber risks. The systems are required to be connected as well as integrated for data sharing, supply chain integration, predictive maintenance, and more, while remaining secure from cyber threats.  Let’s dive into the key strategies for securing legacy OT systems in the modern manufacturing environment.

Zero Trust Architecture

This approach is a perfect technique to secure traditional systems for modern cybersecurity requirements.  Operating on the principle of ‘never trust, always verify’, the Zero Trust model ensures all users, devices, and applications, irrespective of their presence in or outside the organization’s network, are continuously authenticated, authorized, and validated before granting access to the network data and applications.  Here, the principle of least privilege is implemented, where users are provided with the minimum level of access to just do their jobs.  In OT networks, this approach will prevent vendors from accessing networks for more time than required to perform the specified task.  This strategy minimizes the attack surface and prevents lateral movement of attacks and establishes secure connectivity between IT and OT systems.

OT Network segmentation and micro-segmentation

Manufacturing organizations must implement network segmentation by separating IT and OT environments and further apply micro-segmentation of OT networks to isolate all critical assets from the non-critical ones.  The zones are segmented based on the asset type, function, and criticality. By doing so, it limits the attack surface and the damage caused by a cyber incident.  Micro-segmentation further applies security measures to a granular level, where the attacker is unable to traverse the entire network if they gain access to one of the segments.  OT network segmentation can be implemented by first gaining a complete inventory of the OT devices, followed by mapping their behavior and communication patterns before grouping and designing and deploying the segmentation plan.  Additionally, organizations should monitor and review the network segmentation policies and procedures on a regular basis and ensure they are updated and stay effective.  This strengthens the OT systems, enhances network security, optimizes performance, and ensures business continuity.

Fostering security awareness and training

Human error is a significant risk factor in ensuring the organization is well protected from cyberattacks.  Teams should have a thorough understanding of the attack vectors and the associated risks.  OT personnel and shop floor engineers must be trained on cybersecurity best practices, cybersecurity principles, and procedures for reporting any potential security incident or threat.  At the same time, it is equally important to bridge the cultural gap between IT and OT teams so they are convinced about the shared responsibility they carry in observing cybersecurity.  The awareness training should be an ongoing one to keep the employees informed of any new threats and trends.  By fostering a culture of open communication, teams are encouraged to report any suspicious threats or presence of vulnerabilities. All OT security measures should be regularly reviewed, updated, and tested to ensure they remain effective even with the evolving threats and the techniques used to attack by cybercriminals.