OT Vulnerability Management: A complete guide to securing industrial environments

Industrial and critical infrastructure operators are facing increasing cyber risks as digital transformation and industrial IoT reshapes operational technology (OT) environments. Unlike traditional IT networks, OT systems, industrial control systems (ICS), SCADA, distributed control systems (DCS), and programmable logic controllers (PLCs) require additional and focused vulnerability management attention. Let me explain why.

One of the most pressing yet complex areas of OT cybersecurity is vulnerability management (VM). While vulnerability management is well understood in IT, applying it in OT environments brings unique challenges due to legacy systems, safety implications, and compliance with sector-specific regulations. There are also concerns of impact on businesses operations which is why patching is often delayed or left at the discretion of the OEM.

Today’s post provides a comprehensive guide to OT vulnerability management, including the consequences of neglecting VM, practical steps for building a program, best practices, and recommendations from IEC 62443, NERC CIP, NIS2, and NIST CSF.

As always you can read our last post on NIS2 compliance for the oil and gas sector here.

Why OT Vulnerability Management matters

In IT, patch management and vulnerability scanning are routine. In OT, however, systems often run on outdated operating systems, vendor support is limited, and unplanned downtime can lead to catastrophic consequences and loss of production time.

When an OT operator runs operations without a structured OT vulnerability management program, their organizations are exposed to:

· Unpatched systems vulnerable to known exploits (e.g., WannaCry, Industroyer2, Triton/Trisis).

· Supply chain risks, where third-party vendor software contains exploitable flaws.

· Regulatory non-compliance, leading to fines and reputational damage.

· Process disruptions, ranging from production halts to unsafe plant conditions.

· National security risks, as many OT environments underpin critical infrastructure.

Consequences of not having a structured OT Vulnerability Management Program

The absence of a VM program in OT can have far-reaching impacts.

· Increased cyberattack risk: Threat actors such as those belonging to state-sponsored groups to cybercriminals, actively target known OT vulnerabilities. A lack of patching leaves systems open to exploitation.

· Operational disruptions: Malware such as NotPetya spread into OT networks, crippling global logistics and manufacturing. Without VM, these events are more likely.

· Safety hazards: Vulnerabilities in PLCs or HMIs can allow attackers to manipulate physical processes, leading to equipment damage or even loss of life.

· Regulatory penalties: Regulations like NERC CIP in North America and NIS2 in Europe mandate risk-based vulnerability management. Non-compliance can result in significant fines.

· Erosion of trust: Customers, regulators, and investors expect resilience. A major incident tied to poor VM practices can damage credibility and market standing.

· Long term risks: Unaddressed vulnerabilities accumulate over time, creating technical debt that becomes harder and costlier to remediate. This not only weakens security posture but also hampers modernization efforts, limits scalability, and leaves the organization perpetually exposed to evolving threats.

What is the right way to approach OT Vulnerability Management

Implementing a VM program in OT requires careful adaptation of IT practices while considering the unique nature of industrial environments.

Step 1: Establish asset visibility

You cannot secure what you cannot see. Start with a comprehensive OT asset inventory that includes firmware versions, software dependencies, and network interconnections. Passive discovery tools are preferred to avoid disrupting sensitive systems. A clear view of assets and asset behaviors is not just desirable but essential.

Step 2: Risk-based vulnerability identification

Use threat intelligence, vendor advisories, and vulnerability databases (e.g., ICS-CERT, NVD) to map vulnerabilities against your assets. In OT, the operational context rules. A vulnerability on an engineering workstation controlling a turbine is far more critical than the same vulnerability on a non-critical historian server.

Step 3: Prioritize remediation based on risk

Since patching may not always be possible (due to vendor restrictions or downtime risks), organizations should rank vulnerabilities by:

· Exploitability (is it weaponized in the wild?)

· Asset criticality (impact on safety, reliability, and compliance)

· Exposure (can it be accessed remotely or only locally?)

· Links to processes

Step 4: Define mitigation options

Options can go beyond patching:

· Compensating controls such as segmentation, firewalls, and application whitelisting.

· Network monitoring to detect attempts at exploiting known vulnerabilities.

· Change management alignment, ensuring patches are tested in lab environments before deployment.

Step 5: Integrate VM into institutional governance and compliance frameworks

Embed OT vulnerability management into existing security governance, ensuring reporting structures, ownership, and metrics are defined.

Best practices for OT vulnerability management

· Adopt an ongoing process with continual enhancements : VM is not a one-time project but a lifecycle activity involving identification, assessment, remediation, and validation.

· Micro segmentation and defense-in-depth: Even if patching is delayed, segmenting critical assets reduces the blast radius of an exploit.

· OEM/vendor Collaboration: Work with equipment manufacturers to understand patch cycles, supported mitigations, and end-of-support timelines.

· Patch testing in a safe environment: Always validate patches in a controlled lab before applying them to live OT systems.

· Leverage OT-specific threat intelligence: Subscribe to industry-specific ISACs and advisories for real-time awareness of relevant vulnerabilities.

· Align with business risk appetite: Decisions around patching and compensating controls should be made jointly by security, engineering, and operations.

· Automate wherever possible: Automated asset discovery and vulnerability correlation tools such as Shieldworkz can reduce manual effort and improve accuracy.

OT Vulnerability Management and key cybersecurity standards

Several global standards and regulations provide ample guidance on vulnerability management in OT environments.

IEC 62443

· IEC 62443-2-3 specifically outlines patch and vulnerability management processes for IACS (Industrial Automation and Control Systems).

· Recommends maintaining asset inventory, assessing vulnerabilities, and applying patches or compensating controls within acceptable risk levels.

NERC CIP

· CIP-007-6 R2 mandates tracking, evaluating, and installing security patches for critical cyber assets in the North American power sector.

· Utilities must document patch evaluations and mitigation strategies for unpatched systems.

NIS2 directive

· Expands scope to essential and important entities across the EU.

· Requires risk-based vulnerability management, including timely application of patches and security updates.

· Non-compliance can lead to heavy financial penalties.

NIST cybersecurity framework (NIST CSF 2.0)

· Under the protect (PR.IP) and Identify (ID.AM) functions, vulnerability management is explicitly recommended.

· Promotes integrating VM into broader risk management, aligning IT and OT practices.

What an OT Vulnerability Management program should look like?

An effective OT VM program should include:

Governance and ownership

· The CISO provides overall governance.

· The OT Security Manager coordinates program execution.

· Engineering and operations teams own implementation and downtime planning.

· Vendors play a key role in patch validation and advisories.

Policy framework

· Define scope, responsibilities, and risk thresholds.

· Establish patch cycles, risk acceptance criteria, and escalation processes.

Processes and workflows

· Asset inventory and classification.

· Vulnerability scanning (passive first, active where safe).

· Patch and mitigation evaluation.

· Risk-based prioritization.

· Change management integration.

· Continuous reporting and metrics.

Technology enablement

· Passive OT monitoring tools.

· Vulnerability correlation platforms with ICS-CERT/NVD feeds.

· Secure remote access for vendor collaboration.

Metrics and KPIs

· Mean time to detection (MTTD)

· Mean time to remediation (MTTR) for high-risk vulnerabilities.

· Percentage of assets covered in VM.

· Number of unpatched critical vulnerabilities accepted with compensating controls.

Challenges and How to Overcome Them

· Legacy Systems: Many OT assets run unsupported OS versions. Use segmentation and compensating controls when patches are unavailable.

· Downtime Constraints: Coordinate with operations to align patching with maintenance windows.

· Cultural Resistance: Engineers may resist patching for fear of disruption. Building cross-functional governance helps bridge this gap.

· Vendor Dependency: Some vendors restrict patching; in such cases, enforce contractual clauses for timely updates.

OT vulnerability management is not just about compliance. Instead, it is about ensuring the safety, reliability, and trustworthiness of critical operations. Organizations that invest in proactive VM reduce their exposure to disruptive attacks, avoid regulatory penalties, and gain resilience in an increasingly hostile cyber threat landscape.

By aligning with standards like IEC 62443, NERC CIP, NIS2, and NIST CSF, and by embedding VM into the broader cybersecurity and operational risk governance model, industrial operators can strike the right balance between safety, reliability, and security.

Key takeaways

· OT vulnerability management is essential for reducing cyber, operational, and safety risks.

· The absence of a VM program leaves organizations exposed to ransomware, supply chain attacks, and regulatory fines.

· A structured, risk-based approach, prioritizing visibility, assessment, remediation, and compensating controls, is critical.

· Best practices include vendor collaboration, continuous monitoring, segmentation, and governance alignment.

· IEC 62443, NERC CIP, NIS2, and NIST CSF all emphasize vulnerability management as a core requirement.

· A successful program requires shared ownership between CISO, OT security managers, and engineering teams.

 Interested in learning about how you can launch and sustain an OT vulnerability management program? Talk to our OT vulnerability risk management expert.