Answer yes if your organisation keeps an up-to-date inventory of all OT hardware and software assets, listing asset owners and details such as version numbers, business usage, and location. Include details in the notes.
An up-to-date inventory of Operational Technology (OT) hardware and software assets, such as Programmable Logic Controllers (PLCs), Remote Terminal Units (RTUs), and SCADA servers, is a foundational requirement for securing an OT environment.
OT environments are particularly prone to inventory gaps compared to IT, because assets are often long-lived, deployed by different teams or contractors over time, and connected via specialised networks that general IT asset discovery tools may not cover. Without a reliable inventory, organisations risk leaving legacy or forgotten devices unpatched and unmonitored, struggling to scope the impact of a vulnerability or incident accurately, and being unable to demonstrate to customers or regulators exactly what is running within the OT environment supporting the products or services provided. Maintaining this inventory as a living record, rather than a point-in-time exercise, ensures it remains a reliable foundation for the rest of your OT security practices.
Establish a comprehensive inventory covering all OT hardware and software assets within the scope of the products or services you provide, including PLCs, RTUs, SCADA servers, Human-Machine Interfaces (HMIs), engineering workstations, and any specialised OT networking equipment. For each asset, you should typically record:
To keep the inventory reliable over time, you should typically:
- Establish a process for adding new assets to the inventory as part of any procurement, deployment, or commissioning process, rather than relying solely on periodic manual audits to catch additions.
- Use OT-aware asset discovery tools where appropriate, recognising that many general IT discovery tools don't safely or accurately identify OT devices.
- Reconcile the inventory against physical and network reality on a regular basis, since undocumented or "shadow" OT assets are a common finding when inventories are checked against what's actually deployed.-Retire assets from active use formally, updating the inventory to reflect decommissioning rather than leaving retired assets listed as active (or vice versa).