Next is Now - Increase Visibility of Your Critical OT Assets and Take Control

 The Visibility Gap: A Persistent OT Challenge

Despite increased investments in digital transformation, many industrial organizations still lack a consistent, methodical approach to OT asset discovery, classification, and lifecycle management.

In conversations with clients and across multiple OT assessments, we continue to see:

• Fragmented OT inventories across plants and business units
• Unknown assets operating inside critical production networks
• Limited visibility of legacy equipment and unsupported systems
• Manual updates that quickly become outdated
• Missing correlations between assets, production processes, risks, vulnerabilities, and incidents

Without real-time visibility, teams cannot confidently answer fundamental questions: What do we have? Why do we have it? Where is it? What does it connect to? Is it secure?

Why OT Asset Discovery is different from IT

IT environments have largely standardized around modern operating systems, agent-based tools, and mature lifecycle processes. OT is not the same — and cannot be treated the same.

Key differences include:

• Long asset life cycles (often 20–30 years)
• Proprietary protocols with minimal documentation and limited ability to respond to discovery prompts
• Legacy systems fragile to network scans
• Complex network architectures – not designed for asset discovery
• Strict availability requirements that restrict intrusive activities
• Decentralized responsibilities across engineering, production, and IT teams

For these reasons, OT visibility typically requires a combination of discovery methods — each suitable for different parts of the environment.

Modern Methods of OT Asset Discovery

1. Manual Capture

Essential for isolated networks or legacy systems that cannot be scanned.

Used during commissioning or vendor handover, but prone to gaps if not continuously updated.

2. Configuration Analysis

Extracting information from:

• engineering workstation project files,
• change management records,
• vendor documentation.

Provides a useful context but depends on process maturity.

3. Agent‑Based Insights (Indirect)

While agents are not deployed on PLCs or RTUs, data from:

• servers,
• engineering workstations,
• patch management tools

can enrich the OT asset picture.

4. Active Identification

Controlled scans that query devices directly.

Accurate, but risky for older OT systems and must be carefully governed.

5. Passive Network Monitoring

The safest and most widely adopted method in OT. By analyzing real network traffic, passive discovery tools identify:

• device types,
• firmware,
• communications,
• vulnerabilities,
• abnormal behavior.

This approach aligns well with industrial IDS and cyber monitoring deployments. However, organizations should explicitly incorporate OT asset discovery as a design requirement when selecting or deploying OT IDS solutions. In such cases, the resulting architecture and deployment model may differ from those intended for OT monitoring alone.

Good Practices for Achieving Reliable OT Visibility

To build accurate OT inventory and minimize operational risk, organizations today increasingly adopt a hybrid discovery approach. Passive monitoring remains the safest foundation, but on its own often lacks the detail required for complete asset intelligence. For this reason, many OT teams complement passive methods with carefully governed active or selectively‑active techniques that are specifically designed not to disrupt industrial processes.

Some OT assets — such as operator workstations, servers, and newer controllers — can be actively scanned, but only after thorough verification and approval from engineering teams, as safety and process stability must always come first. Alternatively, deeper active identification can be performed during scheduled maintenance windows, when operational risk is reduced.

To support this hybrid model, organizations should:

• Choose solutions designed specifically for OT environments
• Use passive TAPs or SPAN ports to safely detect and classify OT assets based on real network communications
• Automate continuous discovery rather than rely on periodic snapshots
• Define central governance, ownership, and the roles responsible for sustaining the process.
• Integrate OT data with IT and enterprise systems for context and action.

This blended model safeguards industrial processes while creating a more complete and trustworthy view of OT assets, providing the foundation needed for more connected, insight‑driven and resilient OT operations.

From Local Inventories to a Central OT Asset Management Model

While some organizations maintain plant‑level inventories, the trend is shifting toward centralized OT asset management within an enterprise CMDB:

Local Inventory

• Useful for plant engineering teams
• Limited visibility at the enterprise level
• Hard to scale, maintain, or correlate with risks

Central (CMDB‑Driven) Inventory

A centralized approach supports a wider range of operational and security processes:

• Change Management
• Vulnerability Response
• Incident Response & Forensics
• Risk and Compliance Management
• Reporting, KPIs, and ROI measurement

A unified view enables both plant-level and enterprise-level decisions.

Service Mapping in OT (ServiceNow Perspective)

In industrial environments, understanding asset relationships is as important as knowing the asset itself. A single outdated firmware version can impact an entire production line.

ServiceNow® Service Mapping provides:

• Hierarchical modeling of OT devices and production systems
• Contextual visibility into upstream and downstream dependencies
• Automatic mapping of equipment based on subnet or protocol logic
• Integration with change, incident, vulnerability, and compliance workflows

This context transforms raw asset lists into operational intelligence — the foundation of an OT Control Tower.

A Platform‑Based Approach: The ServiceNow OT Solution

1. Foundation

Uses Purdue Model levels and data from multiple OT discovery sources to establish a strong inventory baseline.

2. Visibility

Delivers a complete view of OT systems, dependencies, and real-time status — enabling smarter decisions.

3. Vulnerability Response

Correlates vulnerabilities with specific OT assets to help teams prioritize based on risk, criticality, and operational constraints.

4. Service Management

Connects OT assets to digital workflows, so incidents, changes, and maintenance activities are structured, traceable, and efficient.

Conclusion:

Fast, uncontrolled OT asset discovery can be risky — it may disrupt operations or miss critical dependencies.

But responsible, continuous, platform‑driven OT asset discovery and service mapping enables informed decision‑making without jeopardizing uptime.

Process maturity and clear ownership structures are essential to sustain these capabilities, ensuring that asset data remains accurate, actionable, and governed. Equally important is keeping a “human in the loop” — engineering and OT security teams must validate findings, interpret context, and oversee automated decisions.

ServiceNow® provides a unified way to discover OT assets, map industrial processes, monitor threats, and connect insights with action.

This helps organizations eliminate blind spots, prevent data breaches, maintain compliance, and operate their industrial environments with confidence.