The recent ransomware attacks on critical infrastructure organizations have highlighted the need for robust OT cyber security. However, the risk factors that threaten OT systems are inherently different from those of IT environments.

For example, connecting air-gapped OT networks to IT systems opens them to the entire threat landscape. Privileged users pose the greatest threat, using their access to exploit OT systems for unauthorized lateral movement.

Implement a Comprehensive OT Security Strategy

While securing operational technology from cyberattacks requires a multi-layered approach, the journey begins with a solid foundation: a detailed inventory. This inventory, encompassing all equipment, accounts, software, and network connections, is a critical roadmap for securing your OT environment. Manually compiling this information through spreadsheets can be time-consuming and prone to errors. However, utilizing tools that can communicate directly with assets in their native protocols offers a more accurate and complete picture, equipping you to identify vulnerabilities, prioritize risks, and implement targeted security measures with greater confidence.

Once an OT security team has a complete inventory of all the assets they are protecting, they can perform the Identify component of their risk assessment. This allows them to create a prioritized list of vulnerabilities and formulate a remediation roadmap.

Unlike IT systems, many OT components are tied to critical industrial processes, and exploiting any vulnerability could have severe consequences. This, coupled with operational constraints that limit the window of time for changes, can make implementing effective measures challenging.

Additionally, OT teams often have cultural resistance to change due to concerns about disruptions and unfamiliarity with new technologies. This makes bridging these gaps challenging, but it is crucial for ensuring a robust OT security program.

Perform Regular OT Security Scans

With traditional IT cybersecurity tools not appropriate for OT systems, defenders must implement a solution that can be adapted to the OT environment. One such tool is a system vulnerability assessment that can identify and prioritize vulnerabilities at the asset level.

Unlike IT cyberattacks that cause productivity delays, OT attacks can have severe physical consequences — including disruption of production processes that can lead to loss of revenue and the need for costly product recalls. As a result, OT security is top of mind for operations executives who face scrutiny from boards of directors.

OT vulnerabilities can be exploited by various threat actors, from hacktivists to disgruntled employees and nation-states. Attacks on OT assets can impact productivity and cause damage to equipment. For example, a successful ransomware attack can disrupt production and cause product recalls. In 2021 alone, 64 OT cyberattacks were reported, with many resulting in expensive shutdowns at companies such as Merck, Mondelez, Maersk, Norsk Hydro, and others, costing billions in lost revenue. To avoid such losses, OT teams must integrate security into the balanced scorecards that drive operational priorities – efficiency, quality, and environmental health.

Implement OT Threat Detection

In a manufacturing environment, the synchronization of machinery and sensors is crucial. A minor disruption could lead to production delays, cost overruns, and customer dissatisfaction. In addition, it can open the door for industrial espionage, where stolen IP could damage a company’s competitive advantage.

While many IT security tools can’t be used in OT environments, effective strategies can be implemented to minimize risks without significant process disruptions. These strategies include continuous OT monitoring, enabling OT asset visibility and inventory management, and risk-based vulnerability management.

Since OT devices communicate over native communication protocols, a patented active querying solution like Tenable’s can detect and discover OT assets – including PLCs, HMIs, and DCSs – at the device level without disrupting operations. This approach helps ensure a comprehensive and ongoing view of the OT attack surface, especially in complex sites with islanded/air-gapped assets. It also allows organizations to uncover hidden risks in OT networks that are not visible using traditional network monitoring. This is a critical step in implementing adequate OT cyber security.

Implement OT Vulnerability Management

Malicious actors are constantly seeking vulnerabilities to exploit, and if an attack succeeds, the results can be devastating. Effective OT vulnerability management protects against these threats, reducing the risk of unauthorized access or process manipulation.

The security threat landscape has changed as OT becomes more digital and connected. OT device protection from known vulnerabilities is one of the new difficulties that security professionals face due to the convergence of IT and OT networks.

OT vulnerability management involves more than just monitoring for existing threats; it also ensures that a device’s security controls remain functional and practical, mainly if they are under pressure due to ongoing operations. A layered approach to OT vulnerability management includes continuous and passive IT/OT threat detection, comprehensive asset visibility, patch management, and configuration control.

OT vulnerability management should also include the ability to manage access by employees, contractors, and vendors, whether on-site or connecting remotely. This can be achieved through granular security that eliminates the need for VPNs while enabling workers to access the applications they need without interfering with production processes or productivity.

Implement OT Access Control

OT assets are vulnerable to attacks that can damage equipment, disrupt services, and cause financial harm or even loss of life. Direct attacks can target a specific piece of OT equipment, such as a power grid or water plant control system, causing a malfunction that affects operations. Alternatively, attackers can target the systems themselves for sabotage or espionage purposes.

To reduce OT cybersecurity vulnerabilities, it’s important to establish security policies that enforce the least privilege. These policies ensure that only those who require access have it and can be audited and restricted accordingly. This requires strong governance of privileged accounts and passwords in a zero-trust environment.

Additionally, it’s critical to secure OT networks with solid firewalls and granular access controls. This helps prevent rogue devices from connecting to an OT network and introducing malware or strains of existing malware into the system. It also enables administrators to monitor and record all remote sessions to identify unauthorized activity or suspicious behavior. These capabilities, IT/OT threat detection, asset inventory, and configuration control will allow organizations to reduce OT risks without impacting operations.