Top 15 OT Asset Discovery Tools to Improve Visibility

Why OT asset discovery matters

• You can’t protect what you can’t see. Accurate inventories are the foundation of vulnerability management, segmentation, incident response and regulatory compliance.
• OT environments are heterogenous and fragile: many devices don’t support agents and some active scans can disrupt operations. That makes agentless, protocol-aware discovery essential.
• Modern solutions pair discovery with context (firmware, serial, asset role, communications map) so teams can prioritize risk and automate containment.

How OT asset discovery works – modes & core techniques

1. Passive network monitoring (recommended for OT): mirror traffic (SPAN/tap) and fingerprint devices using deep-packet inspection (DPI), protocol semantics (Modbus, DNP3, OPC-UA etc.) and behavioral patterns – safe for production.
2. Active queries / safe protocol-aware scanning: targeted queries that use protocol semantics to ask a device for identity without sending disruptive payloads. Best when used carefully.
3. Hybrid (passive + selective active): passive baseline + scheduled non-disruptive scans to fill gaps – most enterprise OT products use this approach.
4. Agented discovery (where possible): for IT/Windows/Linux endpoints that can host agents – not always possible on PLCs.

Quick selection criteria (what to evaluate)

• Non-intrusiveness: passive-first and protocol-aware scanning.
• Industrial protocol library: ported DPI for OT protocols and ongoing protocol updates.
• Asset context enrichment: firmware, serial, role, physical location, business-owner.
• Network mapping & topology: zone/conduit views to support Purdue-model segmentation.
• Integrations: SIEM, IT asset CMDB (ServiceNow), firewalls, NAC, ticketing.
• Scalability & remote-site support: for distributed sites and harsh networks.
• Vendor OT expertise & research (threat intel for ICS).

The top 15 OT asset-discovery tools (short vendor summary + why/when to pick)

1. Claroty (Claroty Platform / Continuous Threat Detection)

Why it stands out: Industry-focused platform with a mature protocol DPI library and multiple discovery methods (passive, active, agent where possible). Strong for large industrial estates and compliance-driven programs.
Best for: Utilities, oil & gas, large manufacturing that need deep protocol coverage and exposure management.

2. Nozomi Networks Guardian

Why it stands out: Market leader in passive traffic-based discovery and real-time network visualisation – accurate asset inventories, long protocol support and scale for critical infrastructure.
Best for: Sites needing continuous passive monitoring with excellent OT visualization.

3. Dragos Platform

Why it stands out: Built specifically for ICS/OT defenders – automated discovery combined with classification, process context and threat hunting capabilities. Dragos emphasizes OT-specific workflows and threat modelling.
Best for: Organizations that want asset discovery embedded in an ICS-focused detection/IR workflow.

4. Tenable.ot (formerly Indegy capabilities)

Why it stands out: Strong asset inventory and mapping, prioritisation by firmware/OS and configuration, plus integrations with broader vulnerability management. Good for teams already using Tenable.
Best for: Enterprises standardising on Tenable for vulnerability discovery and wanting OT context.

5. Armis (Armis Centrix / Armis for OT)

Why it stands out: Agentless, cloud-first approach with broad IT/IoT/OT coverage and deep enrichment to create accurate inventories. Good for mixed environments.
Best for: Enterprises with converged IT/OT and unmanaged IoT fleets.

6. Forescout (Forescout Platform / OT solution)

Why it stands out: Real-time asset inventory, active + passive discovery options and strong NAC/segmentation integrations (ideal for bridging OT/IT control).

Best for: Organisations that need real-time control enforcement combined with discovery.

7. Microsoft Defender for IoT (formerly CyberX integration)

Why it stands out: Microsoft’s enterprise-grade OT/IoT discovery, integrates with Defender stack; provides device inventory, risk-based vulnerability management and analytics. Especially useful for customers invested in Microsoft security stack.
Best for: Organisations using Microsoft security tools seeking tight integration and centralised management.

8. Darktrace / OT

Why it stands out: Self-learning AI to establish device “pattern of life” and surface unknown assets and anomalous communications; useful where behavioural baselining matters.
Best for: Sites that want unsupervised behaviour-based discovery and anomaly detection.

9. SCADAfence

Why it stands out: Focused OT/IoT platform with device-type learning, customisable asset types and strong enterprise integrations for automated inventory and governance.
Best for: Manufacturers and enterprise OT teams that need customizable device learning and governance.

10. Cisco Cyber Vision

Why it stands out: Cisco’s OT visibility product uses passive and safe active queries, precise protocol awareness and fits well in Cisco-centric networks. Good for customers using Cisco networking and segmentation controls.

Best for: Organisations with Cisco infrastructure and a need for network-level OT context.

11. Radiflow (iSID)

Why it stands out: iSID provides passive discovery with anomaly detection, data enrichment and active scanner options – strong at mapping asset roles and operational impact.
Best for: Utilities, transportation and process industries needing OT-focused threat detection plus inventory.

12. Kaspersky Industrial CyberSecurity (KICS)

Why it stands out: Kaspersky’s industrial suite offers asset inventory, passive/active data collection and OT process monitoring backed by ML analytics. It’s an OT-aware XDR-style product.
Best for: Organisations looking for an OT platform that bundles discovery with anomaly detection and managed services.

13. Fortinet (FortiNAC / Fortinet OT Security stack)

Why it stands out: Fortinet combines NAC, asset discovery and network enforcement with OT visibility features – useful for security fabrics that push policies to enforcement points.
Best for: Enterprises that want discovery tightly coupled to network enforcement and segmentation.

14. Honeywell (Honeywell Cyber Insights / Forge Cybersecurity)

Why it stands out: Honeywell’s OT product family is tailored to process industries and integrates discovery, vulnerability mapping, and OT-specific insight – certified for some control platforms, making it low-risk for certain brownfield sites.
Best for: Process-control environments (refineries, petrochemical, heavy industry) that prefer vendor-certified solutions.

15. Ordr (Ordr SCE / OrdrAI)

Why it stands out: Ordr’s asset-intelligence platform focuses on automated discovery, AI classification and policy automation. Strong in multi-vendor, multi-site environments with lots of unmanaged devices.
Best for: Organisations that want single-pane device intelligence for IT/OT/IoMT and automated policy generation.

Practical deployment tips – keep operations safe

1. Start passive: deploy mirrors/taps and passively build the initial asset inventory. Passive is safe for production OT.
2. Segment your rollout: pilot on a non-critical cell or test VLAN before full production.
3. Hybrid only when validated: use protocol-aware active queries with vendor guidance and change windows.
4. Enrich inventory: feed asset data into CMDB/ServiceNow and tie to owners and maintenance processes. (Most vendors provide connectors.)
5. Use asset context to prioritize: firmware age, presence of unsupported protocols, patch state and known-exploited CVEs should drive remediation priorities.

Common pitfalls and how to avoid them

• Blind reliance on a single discovery method: combine passive DPI, targeted active queries and IT data sources.
• Thinking discovery is “one-and-done”: inventory is fluid – schedule continuous discovery and reconciliation.
• Failure to validate false positives: OT naming, virtualization and NATs can cause duplicate entries – validate with engineers.
• Not involving OT engineers early: discovery outputs must be contextualised by operations teams to avoid false alarms and unnecessary disruption.

How to pick the right tool – short checklist

1. Use-case fit: protection (detection/IR), inventory + remediation, enforcement (NAC/segmentation) or full OT platform?
2. Protocol coverage: does the vendor support your legacy/proprietary protocols?
3. Integration needs: SIEM, CMDB, firewall, NAC, ticketing.
4. Operational risk: passive-first, non-intrusive scanning, vendor proof for safe active queries.
5. Scale & remote sites: lightweight sensors, cloud vs on-prem management.
6. Industry knowledge & threat intel: ICS-focused vendors bring ICS playbooks and threat intel that generic IT vendors may lack.

Quick migration blueprint (30 / 60 / 90 day)

• Days 0–30: baseline with passive taps on a pilot cell, produce the first asset inventory and reconcile with CMDB. (Use Claroty/Nozomi/Dragos/Ordr to get quick clarity.)
• Days 30–60: enrich inventory (firmware, serials, owners), add integrations (SIEM, ServiceNow, NAC), and validate asset classifications with OT teams.
• Days 60–90: start safe active scans where required, configure risk-scoring and automated policy pushes to enforcement tools (NAC/firewall) with rollback plans.

Final recommendations – pull it all together

• For deep ICS expertise + threat hunting choose Dragos or Claroty.
• For passive network-scale visibility and mapping, Nozomi, SCADAfence or Radiflow are excellent.
• If you must bridge IT/OT and manage large unmanaged IoT fleets, consider Armis, Ordr or Forescout.
• If you already run a Microsoft or Cisco stack, Defender for IoT or Cisco Cyber Vision will accelerate integration.

Resources & further reading

• Claroty – Continuous Threat Detection & Asset Inventory.
• Nozomi Networks – Guardian OT visibility & asset mapping.
• Dragos – Asset visibility and ICS-specific context.
• Tenable.ot – OT asset inventory & mapping.
• Armis, Forescout, Microsoft Defender for IoT, Darktrace/OT, SCADAfence, Cisco Cyber Vision, Radiflow, Kaspersky KICS, Fortinet OT features, Honeywell Cyber Insights, Ordr (vendor pages referenced throughout).

Closing note

Asset discovery is not a checkbox – it’s the baseline for a pragmatic OT security program. Choose tools that respect production constraints, integrate with your operational processes and give engineers usable context (not just alerts). Start passive, measure impact, then automate containment only after you’ve validated the inventory and mapping with operations teams. If you’d like, I can convert this into a downloadable checklist or a vendor-comparison table (feature × capability) so you can run pilot evaluations across your plant network – tell me which vendors you’re considering and I’ll build the matrix.