A Guide to OT Vulnerability Management

OT systems have traditionally remained separate from the expansive connectedness of the corporate network. But over the last two decades, organizations have connected the two in order to gain efficiencies and scale. This poses a major security problem for critical infrastructure industries—including Manufacturing, Energy, Utilities, Transportation, and Healthcare—all of which have come under an increased number of threat vectors in recent years.

This brief guide will help you to understand exactly what OT vulnerability management is and how your organization can approach it, including best practices for establishing a robust program.

 

What Is OT Vulnerability Management?

It is the program put in place to minimize the volume and impact of exploitable conditions across the enterprise, its networks, and technologies that could impact the safety, reliability, and functionality of industrial processes. It is a broad program that captures vulnerability data and transforms it into action to ensure long-term organizational resilience.

According to CISA, “the vulnerability management domain focuses on the process by which organizations identify, analyze, and manage vulnerabilities in a critical service’s operating environment.”[i]

 

Vulnerabilities Vs Risks and Threats

Performing vulnerability management properly requires security practitioners to understand the differences between vulnerabilities, risks, and threats. While these terms are often used interchangeably, they have distinct meanings and implications.

Vulnerabilities refer to weaknesses or flaws in a system that can be exploited by attackers and can exist in software, hardware, or even human processes. By contrast, risks involve the potential negative impact or consequences that can arise from the exploitation of vulnerabilities. Threats are the potential sources of harm or danger that can exploit vulnerabilities and cause harm to an organization’s assets. Threats can come in various forms, such as cybercriminals, malware, or even natural disasters.

 

What Are the Specific OT Systems Involved?

According to NIST, the National Institute of Standards and Technology, OT encompasses a broad range of programmable systems and devices that interact with the physical environment or manage devices that interact with it. “Examples include industrial control systems, building automation systems, transportation systems, physical access control systems, physical environment monitoring systems, and physical environment measurement systems.”[ii] Within these systems exist key components that could have vulnerabilities, and these components include:

• Sensors and Actuators: Devices responsible for gathering data from the physical environment and initiating actions based on that data. Examples include temperature sensors, pressure sensors, motors, valves, as well as other IoT and IIoT devices..
• Control Systems: Systems that receive data from sensors, make decisions, and regulate physical processes. This category comprises Programmable Logic Controllers (PLCs), Distributed Control Systems (DCS), and Supervisory Control and Data Acquisition (SCADA) systems.
• Network Infrastructure: OT systems depend on a network infrastructure to connect different components and facilitate communication. This involves wired and wireless networks, switches, routers, and firewalls.
• Human-Machine Interfaces (HMIs): Interfaces providing a visual representation of the OT system, allowing operators to monitor and interact with it. HMIs include touchscreens, monitors, and control panels.

 

The Four Main Causes of OT Vulnerability

Most critical infrastructure organizations have a blend of modern systems and older ones that run their industrial processes. While both new and old come with inherent security issues, the older, outdated OT systems often lack modern security features entirely, making them vulnerable to cybercriminal exploitation. In addition, when organizations converge their OT network with their enterprise-wide IT network, they introduce many new attack points. The sheer volume and diversity of device types provide cyber attackers with the leverage they need to compromise OT assets.

Complexity represents the third cause. By necessity, OT environments are complex. This makes it difficult to detect and respond to vulnerabilities effectively, especially since many OT systems cannot incur downtime. Yet, security teams must recognize the criticality of securing each element of an OT system, as a security lapse in one component can render the entire system vulnerable to cyber threats.

Finally, many modern OT products continue to fall short of ‘secure-by-design’ characteristics. Our own recent research from our Vedere Labs demonstrates the continuing prevalence of insecure-by-design practices in OT products and highlights that they lead to broken security controls. Moreover, vendors often release low-quality patches that result in new vulnerabilities rather than eliminating them.

 

The Challenges

Most critical infrastructure organizations recognize the need to address their OT vulnerabilities. Yet, the tools they use and the strategies they follow often fall short of fully identifying OT vulnerabilities and addressing them in a timely and robust manner. These challenges include strategies:

1. Lack of OT Asset Visibility: Many OT assets use proprietary protocols that make them virtually invisible to traditional IT security tools. This leads to a gap in profile data associated with each OT asset, making it  difficult to assess and manage its vulnerabilities.
2. Standard Vulnerability Scanners Fall Short: Common vulnerability scanners used in traditional IT environments can disrupt OT operations due to the large volume of traffic they generate. OT environments often cannot handle such traffic volumes and can shut down as a result of the use of these scanners.
3. Poor Vulnerability Prioritization Strategies: Even when a critical infrastructure organization knows about all the vulnerabilities that exist in its OT environment, it still needs to decide which vulnerabilities to address first.  Too many organizations lack a methodology and the right tools to properly organize their  discovered vulnerabilities.
4. Patching Lapses: A vulnerability management process must account for regular patching of known vulnerabilities. Trying to do this manually is impossible, given the vast number of vulnerable systems, tools, and software types involved.

 

Best Practices

A best practice process enables an organization to identify, prioritize, and fix vulnerabilities effectively. By following a step-by-step process, such as a risk assessment, organizations can ensure that their systems and networks are secure from potential threats.

1. Step-by-step process to implementing a vulnerability management process: Start by conducting a comprehensive risk assessment to identify potential weaknesses in your infrastructure. For example, you can start by looking at the most critical CVEs as tracked by CISA and other threat intelligence sources, and act on the ones that affect your infrastructure the most based on their severity and impact. xCreate a plan that includes timelines and responsible parties. Regularly review and update your process to adapt to new threats and technologies.
2. Vulnerability identification, prioritization, and remediation: Utilize scanning tools to continuously monitor your systems for vulnerabilities. Implement a risk-based approach to vulnerabilities based on their potential impact on your organization. Ensure clear communication and collaboration between IT teams and stakeholders to expedite the process.
3. Automated vulnerability management for increased efficiency: Leverage technology solutions, such as Forescout’s 4D Platform™, to streamline vulnerability identification and fixes, saving valuable time and resources. With built-in workflows and real-time insights, organizations can enhance their security posture and respond quickly to emerging threats.

By implementing a robust process and leveraging automation tools, organizations can effectively mitigate security risks and protect their valuable assets from potential vulnerabilities.

 

Unifying Management Across OT, IoT, and IT

With industrial environments increasingly dependent on digital systems for production, organizations need a holistic approach to asset discovery, assessment, management and governance. The digital transformation of OT environments demands a force multiplier – a single platform that automates every step in the cybersecurity continuum.

Complete security starts with an accurate asset inventory, where they are located and their compliance status. With rapid digitalization of critical infrastructure—often geographically dispersed across large sites—accurately identifying and managing all OT, IoT and IT assets is increasingly challenging.

Industrial assets use proprietary protocols and are more fragile than most which makes them and the processes they support difficult to identify. Discovery approaches that work for IT and IoT might not work for sensitive OT devices given safety rules, vendor interoperability issues, industrial process requirements and other considerations. Especially when OT devices control critical infrastructure, there can be no downtime or service disruption. Therefore, they require non-intrusive passive monitoring or agentless techniques.

Forescout offers continuous discovery of all cyber assets across all networks, with full visibility into OT networks to detect cyber threats before they lead to operational or security incidents.

 

 

How It Works

Forescout’s in-depth asset management and monitoring of OT networks and device types employs more than 30 passive and active discovery techniques to identify assets, their location and their cyber posture, and to detect anomalies. They include deep packet inspection (DPI) of 300+ IT, OT and IoT protocols as well as carefully selected active queries for OT/ ICS to query selected endpoints, including industrial controllers, and network infrastructure for complete device visibility, well beyond SPAN.

Help Net Security on the capabilities and features of Forescout’s unified solution for identifying and managing vulnerabilities in OT, IoT, and IT hybrid environments:

“Forescout for OT Security unifies multiple use cases into a single, streamlined solution, minimizing manual errors and helping to reduce the complexity of operational workflows.[i] Key features include:

• Comprehensive operational and cybersecurity threat detection rules specifically designed for OT, IoT, and IT hybrid environments
• Expanded capabilities OT discovery and extraction including from network and wireless infrastructure
• Forescout AI-enhanced asset intelligence to track the effectiveness of response actions across the security ecosystem
• Forescout AI reporting with contextual insights about connected devices, potential causes of incidents, and recommended remediation steps
• Role specific dashboards provide custom views for operations, security, SOC analyst, and executive
• Actionable vulnerability prioritization using FS Vedere Labs Known Exploited Vulnerabilities (VL-KEV), an innovative approach to OT/IoT specific exploitation indicators using Vedere Labs’ proprietary threat research (the industry’s largest curated database of actionable insights)
• Asset classification covering 18.7 million unique device profiles from the Forescout Research – Vedere Labs database.”

Our Specific Capabilities

Forescout has several key capabilities to identify and manage OT security vulnerabilities:

• Risk & Exposure Management: Forescout conducts a thorough assessment of all network-connected assets, scrutinizing their security postures and vulnerabilities. It facilitates the implementation of robust security measures such as replacing default credentials, patching vulnerabilities promptly, and adopting a risk-based approach for mitigation. Forescout extends this capability beyond traditional IT networks to encompass OT networks and various types of IoT devices.
• Network Security: Forescout helps organizations avoid exposing unmanaged devices directly to the internet and implements network segmentation to isolate different types of devices. It extends segmentation not only between IT and OT, but also within these networks to prevent lateral movement and data exfiltration. Forescout also implements restrictions on external communication paths and employs isolation or containment measures for vulnerable devices, particularly when immediate patching is challenging.
• Threat Detection & Response: Forescout utilizes IoT/OT-aware monitoring solutions with Deep Packet Inspection (DPI) capabilities to detect and alert on malicious indicators and behaviors. It monitors internal systems and communications for known hostile actions and provides alerts to network operators on anomalous traffic. Additionally, Forescout integrates with threat detection and response solutions to automate response actions across the enterprise, enhancing threat detection and response capabilities.

Explore how Forescout can enhance your OT security program, schedule a demo today.

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[i] CISA. CRR Supplemental Resource Guide, Volume 4, Vulnerability Management, Version 1.1. Accessed July 31, 2025 from the following source: https://www.cisa.gov/sites/default/files/publications/CRR_Resource_Guide-VM_0.pdf

[ii] NIST. NIST Special Publication (NIST SP 800-82r3), Guide to Operational Technology (OT) Security, September 2023.

[iii] Help Net Security Industry News. Forescout for OT Security secures OT, IoT, and IT hybrid environments, September 19, 2024. Accessed July 31, 2025 from the following source: https://www.helpnetsecurity.com/2024/09/19/forescout-for-ot-security/