Operational technology (OT) environments lack sufficient monitoring, and many owners and operators lack a complete and reliable OT asset inventory. Legacy systems, intermittent network traffic, and operational constraints limit what defenders can observe. Without an accurate, continuously updated view of assets and their connections, teams struggle to understand what exists in the environment, how systems communicate, and when changes occur. The result is persistent blind spots across critical systems that weaken detection accuracy, slow investigations, and complicate every downstream cybersecurity and operational process.
When a serious outage occurs without adequate monitoring, investigators and incident response teams find themselves largely in the dark in determining whether the cause was a software or equipment failure, mis-operation, a cyber attack or another factor. The data crossing OT networks is often transitory and, if no provision has been made to record it, it is lost forever.
Building and maintaining a complete OT asset inventory is a continuous process, not a one-time exercise. The Dragos Platform combines passive network monitoring for safe, non-intrusive discovery with controlled, active collection to close coverage gaps and capture critical asset details that traditional IT tools often miss.
Together, these methods create a living, continuously updated inventory that adapts as industrial networks evolve and provides comprehensive visibility across OT systems and communications. In the sections that follow, we’ll explore why asset inventory is so challenging in OT, how passive and active collection work together to keep it complete and accurate, and how that data foundation strengthens detection, investigation, and response while preserving safety and reliability.
Challenges in Capturing a Complete OT Asset Inventory
Maintaining an accurate OT asset inventory is difficult because of the diversity and complexity of assets in industrial networks. These environments include controllers, sensors, relays, operator interfaces, engineering workstations, industrial IoT devices, and other connected systems that each play a unique role in production. Legacy equipment, proprietary industrial protocols, and segmented architectures designed to protect operations make it challenging to observe all activity and maintain context. Many assets communicate only during specific operational events, and manual records quickly become outdated as systems change. Traditional IT discovery tools often miss critical OT assets or create operational risk when used in production environments.
Industrial environments present unique challenges that don’t exist in traditional IT environments. That’s why Dragos takes a layered, multi-source approach to OT data collection—enabling comprehensive visibility while minimizing operational risk.
How Dragos Builds a Comprehensive OT Asset Inventory
The Dragos Platform uses a layered data collection approach to identify and profile assets across industrial networks safely and comprehensively. Asset discovery combines multiple complementary methods to ensure both coverage and accuracy.
Passive Monitoring: The Foundation of OT Visibility
Dragos uses passive sensors and edge collectors as the safest, most scalable way to collect real-time data on OT networks. These components:
- Perform deep packet inspection (DPI) across 600+ ICS protocols.
- Provide automated asset discovery of devices and attributes like make, model, firmware version, and configuration details.
- Enable threat detection, communications baselining, and change monitoring.
- Observe Levels 1 to 3.5 in the Purdue Model without touching live devices.
Passive monitoring is the gold standard in OT because it’s non-invasive, provides continuous coverage, and supports real-time visibility into asset behaviors and network activity. By monitoring network traffic passively, these components establish reliable baselines for normal operations, accurate asset inventories, and early threat detection while managing operational risk.
Active Collection: Extending Visibility and Enriching Data
While passive monitoring provides foundational visibility, certain situations require additional data collection to achieve a complete inventory. Active collection safely extends visibility by capturing asset details that may not appear in network traffic, particularly in environments with limited connectivity or gaps in asset data that passive monitoring cannot fully observe.
Unlike traditional scanning, which can overwhelm sensitive systems, Dragos’s approach to active collection is controlled, deliberate, read-only, and OT-safe. Each data request is intentional and protocol-aware, scheduled during planned windows to enrich data without operational risk.
The Dragos Extended Visibility Agent (EV Agent) is a purpose-built software executable deployed directly onto Windows-based OT devices, specifically designed to extend visibility through controlled, active querying. It addresses scenarios where deploying passive sensors isn’t feasible or effective. Centrally managed through the Dragos Platform interface, the EV Agent is designed for strategic deployment by organizations to minimize operational risk and disruption.
Benefits of Active Collection
Active collection adds measurable value when performed strategically and in coordination with operations by:
- Discovering hidden or low-communication assets that would otherwise remain unseen in passive data.
- Improving inventory accuracy and completeness by validating and enriching details such as OS, firmware, and module relationships.
- Enhancing vulnerability management with precise data needed to assess risk and prioritize remediation safely.
- Reducing uncertainty during incident response by providing verified context about asset configurations and dependencies.
- Supporting compliance and audits by validating asset information against operational and regulatory baselines.
Active collection should always be coordinated with operations and performed during planned maintenance windows to maintain process safety and reliability.
Building Your OT Asset Inventory
Dragos delivers comprehensive OT asset visibility through a layered, passive-first architecture that incorporates safe, active data collection when needed. This living inventory forms the baseline for key OT cybersecurity outcomes by enabling risk-based vulnerability management, high-fidelity threat detection, and faster investigation and response.
When organizations can see and understand their OT assets comprehensively, along with how configurations and communications evolve over time, you can reduce mean time to resolution (MTTR) across the full incident lifecycle—from detection through triage and resolution.
Want to see how an accurate asset inventory accelerates each stage of OT cyber defense? Watch our on-demand webinar to discover how to monitor OT environments, contain threats, and respond faster.
