● Cybersecurity Glossary

What is OT (Operational Technology)?

Operational Technology (OT) is the hardware and software used to monitor, control, and automate physical equipment and industrial processes. OT includes systems such as SCADA, Distributed Control Systems (DCS), Programmable Logic Controllers (PLCs), and Human Machine Interfaces (HMIs) that run factories, power plants, water treatment facilities, oil and gas pipelines, and transportation networks. First defined by Gartner in 2006, OT is distinct from Information Technology (IT) in that it directly interacts with the physical world. As IT and OT networks converge, securing these environments has become one of the most pressing challenges in industrial cybersecurity.

OT Definition and core concepts

Operational Technology (OT) refers to the computing systems that manage industrial operations as opposed to administrative ones. Where IT handles email, databases, and business applications, OT handles the physical processes that produce goods, generate electricity, treat water, and move vehicles. NIST defines OT as “programmable systems or devices that interact with the physical environment, or manage devices that interact with the physical environment.”

The term was first published by Gartner in 2006, initially applied to power utility control systems. Over time, it expanded to cover manufacturing, oil and gas, transportation, building automation, and any environment where computers directly control physical processes. OT is not a single technology but a broad category that includes Industrial Control Systems (ICS), SCADA networks, PLCs, sensors, actuators, and the specialized communication protocols that connect them.

What makes OT different from any other computing environment is its relationship with the physical world. When an OT system fails or is compromised, the consequences go beyond data loss. A malfunctioning PLC can damage equipment. A compromised SCADA system can shut down a power grid. A tampered safety system can put human lives at risk. This is why OT environments prioritize availability and safety above everything else.

Key OT systems: SCADA, DCS, PLC, RTU, HMI

OT is not a single technology but a category containing several specialized systems. Each serves a specific function in how industrial facilities monitor and control their operations.

All of these systems fall under the umbrella of Industrial Control Systems (ICS). When cybersecurity professionals refer to ICS security, they mean protecting the full suite of SCADA, DCS, PLC, RTU, and HMI systems that keep critical infrastructure running.

OT vs IT: the fundamental differences

OT and IT share some underlying technologies, but their design priorities are fundamentally different. Understanding these differences is essential for anyone working in industrial environments or OT security:

The most important difference is the consequence of failure. In IT, a security incident typically means data loss or service disruption. In OT, a compromised system can cause physical damage, environmental contamination, or loss of human life. This is why OT security cannot simply copy IT security practices.

IT/OT convergence

For decades, OT networks operated in complete isolation from enterprise IT systems. They used proprietary protocols, ran on dedicated hardware, and had no connection to the internet. Security relied on this physical separation, often called an air gap.

That isolation has largely disappeared. Organizations want to use operational data for business intelligence, predictive maintenance, supply chain optimization, and regulatory reporting. To achieve this, OT systems are now connected to IT networks, cloud platforms, and external services. This process is called IT/OT convergence.

What drives convergence

Several factors push organizations to connect their OT and IT environments. Industrial IoT (IIoT) devices generate operational data that feeds analytics platforms and machine learning models. Enterprise resource planning (ERP) systems need real time production data to optimize scheduling and inventory. Predictive maintenance algorithms analyze sensor data from OT equipment to prevent failures before they occur. Remote monitoring allows engineers to manage geographically distributed sites without traveling to each location.

What convergence creates

Convergence brings operational efficiency, but it also exposes previously isolated OT systems to the entire IT threat landscape. When an OT network is connected to an IT network that has internet access, an attacker who compromises a business email system or a cloud application may be able to move laterally into the OT environment. This is the core security challenge of IT/OT convergence: the operational benefits are substantial, but so are the risks.

OT security challenges

Securing OT environments is fundamentally different from securing IT environments. The same tools and approaches that work in enterprise IT can cause serious problems when applied to industrial systems. Here are the specific challenges that make OT security its own discipline:

Legacy systems that cannot be patched

Many OT devices run operating systems and firmware that are years or even decades old. Some run Windows XP or older versions of embedded Linux that no longer receive security updates. Patching these systems requires stopping production, which may cost thousands of dollars per hour of downtime. Virtual patching through network security devices is the primary workaround: applying IPS signatures at the network level to protect vulnerable devices without touching the devices themselves.

Protocols without built in security

OT protocols like Modbus, DNP3, and BACnet were designed decades ago for reliability, not security. They lack built in authentication, encryption, or integrity checking. Anyone with network access can send commands to a PLC over Modbus without any credentials. Network segmentation and traffic inspection at the protocol level are essential to prevent unauthorized access to OT equipment.

Scanning can break equipment

Standard IT vulnerability scanners send probing packets that OT devices were never designed to handle. An active scan can crash a PLC, reboot an RTU, or trigger a safety shutdown. OT security relies on passive monitoring that observes network traffic without injecting any packets, and on Network Traffic Analysis (NTA) tools that learn the normal behavior of industrial networks and flag anomalies.

Asset visibility is poor

Many organizations do not have a complete inventory of their OT assets. Devices added over decades, often by different vendors and different teams, create environments where no one knows exactly what is connected. Without visibility, security is impossible. OT asset discovery must account for devices that do not respond to standard network scans and use protocols that IT discovery tools do not understand.

Physical safety must come first

In IT security, the response to a detected threat is often to isolate the affected system. In OT, isolating a system might shut down a pipeline, stop a production line, or disable a safety system. Every security response must weigh the risk of the threat against the risk of the response. Safety Instrumented Systems (SIS) must never be compromised by security measures intended to protect other parts of the network.

The “Purdue Model” and network segmentation

The Purdue Enterprise Reference Architecture (also called the Purdue model) is the standard framework for organizing and segmenting industrial networks. It divides the environment into hierarchical levels, each with specific functions and security requirements:

The Purdue model is referenced by the IEC 62443 standard for industrial cybersecurity, which builds on its hierarchical structure to define security zones, conduits, and security levels. Effective OT security starts with proper network segmentation following this model, ensuring that a compromise in one zone cannot propagate freely into others.

Teldat OT Solutions

Teldat provides a comprehensive OT security and networking portfolio through its be.OT solution, designed specifically for industrial environments where standard IT security tools are not appropriate.

be.OT: visibility, control, detection, and protection

Teldat’s be.OT solution addresses the four pillars of OT security. Visibility starts with automated asset discovery that identifies every device on the industrial network, including legacy equipment and devices using proprietary protocols. Control comes through NGFW capabilities with over 1,000 ICS OT application controls and IPS signatures specifically developed for industrial protocols. Detection leverages Network Traffic Analysis (NTA) with AI models that learn the normal behavior of OT networks and detect anomalies, including zero day attacks that signature based systems miss. Protection integrates all of these capabilities into a unified security platform that can respond to threats automatically, deploy countermeasures, and provide centralized management.

Embedded security at the edge

In OT environments, security must be deployed as close to the equipment as possible. Teldat embeds NGFW and IDS/IPS capabilities directly into its networking hardware, so each network node becomes a security enforcement point. This edge security approach prevents threats from spreading laterally between subnetworks and eliminates the need for separate security appliances at every location. Teldat’s embedded security executes on dedicated CPUs, so inspection does not impact the throughput of the network device.

Virtual patching for legacy systems

Since many OT devices cannot be patched directly, Teldat’s IPS signatures act as virtual patches at the network level. Vulnerabilities in PLCs, RTUs, and SCADA software are addressed by blocking exploit traffic at the closest network point, without requiring any changes to the vulnerable devices themselves. This is especially valuable in environments where stopping production for a software update is not feasible.

Unified IT/OT security management

Teldat’s security platform handles both IT and OT threats within a single system, providing a centralized console for visibility and management across converged networks. OT telemetry integrates with be.Safe XDR for AI powered threat detection and correlated response across network, endpoint, and industrial events.

Frequently Asked Questions about Operational Technology (FAQ’s)

❯ What is Operational Technology (OT) in simple terms?

Operational Technology is the hardware and software that monitors and controls physical equipment and industrial processes. It includes systems like SCADA, PLCs, and DCS that run factories, power plants, and water treatment facilities. Unlike IT, which manages data and business applications, OT directly interacts with the physical world.

❯ What is the difference between OT and IT?

IT manages data, business systems, and enterprise networks. OT manages physical equipment and industrial processes. IT prioritizes data confidentiality; OT prioritizes availability and safety. IT systems are refreshed every 3 to 5 years; OT systems may run for 15 to 25+ years. The two are converging as industrial networks become more connected.

❯ What is IT/OT convergence?

IT/OT convergence is the integration of Information Technology systems (business applications, cloud, enterprise networks) with Operational Technology systems (SCADA, PLCs, industrial control systems). Convergence enables operational data to be used for business intelligence and predictive maintenance, but it also exposes previously isolated OT systems to cyber threats from the IT network.

❯ What are the main OT systems?

The main OT systems are: (1) SCADA for centralized monitoring and control across distributed assets. (2) DCS for managing continuous production processes. (3) PLCs for automating specific equipment on the factory floor. (4) RTUs for data collection in remote locations. (5) HMIs for operator interaction with industrial equipment.

❯ Why is OT security different from IT security?

OT security differs because OT systems prioritize availability and safety over confidentiality. Many devices run legacy software that cannot be patched. OT protocols lack built in security. Standard IT vulnerability scanners can crash industrial equipment. OT security requires passive monitoring, virtual patching, Purdue model segmentation, and specialized ICS threat intelligence.

❯ What is the Purdue model?

The Purdue Enterprise Reference Architecture organizes industrial networks into hierarchical levels: Level 0 (physical process), Level 1 (PLCs and RTUs), Level 2 (HMIs and SCADA), Level 3 (MES and historians), a DMZ separating OT from IT, and Levels 4-5 (enterprise IT and cloud). It is the standard framework for OT network segmentation, referenced by the IEC 62443 industrial cybersecurity standard.