For decades, the worlds of information technology (IT) and operational technology (OT) existed as two separate, almost non-interpenetrating universes. The IT world, centered on data, servers and office applications, grew at a frenetic pace. The OT world, encompassing industrial control systems (ICS), SCADA, PLCs and all the machinery that drives factories, power plants or pipelines, lived in its own slow rhythm, isolated from external networks and governed by completely different priorities. In IT, data confidentiality reigned supreme. In OT, business continuity and the physical security of people and machines were absolute imperatives.
But the fourth industrial revolution and the drive to optimize processes have led to an inevitable IT/OT convergence. Manufacturing networks, once fully isolated, have been connected to office systems for data collection, remote management and analysis. This merger, while making business sense, has opened a digital Pandora’s box, exposing sensitive and often outdated industrial systems to a whole range of threats from the IT world. Trying to apply the same security tools and philosophies to both worlds is a straight road to disaster. Understanding their fundamental differences is the first step to building an effective and, most importantly, process-safe security strategy.
Shortcuts
- What is Operational Technology (OT) and how does it differ from traditional IT?
- Why are security priorities different in the OT world (availability, integrity) than in IT (confidentiality)?
What is Operational Technology (OT) and how does it differ from traditional IT?
Operational Technology (OT) is a collection of hardware and software systems that monitor and control physical processes, devices and events in the material world. Simply put, IT manages the data and OT manages the machines. The OT environment includes industrial control systems (ICS), supervisory control and data acquisition (SCADA) systems, programmable logic controllers (PLC), distributed control systems (DCS) and human-machine interfaces (HMI).
The fundamental difference between IT and OT lies in their main purpose and priorities. IT systems are designed to handle and protect information. Their world is bits and bytes. OT systems are designed to operate and protect physical processes. Their world is valves, motors, temperature sensors and assembly lines. This difference in nature translates into completely different perceptions of risk and priorities.
In the IT world, the result of a successful attack is usually the theft or encryption of data, leading to financial and reputational losses. In the OT world, the result of an attack can be the shutdown of an entire factory, damage to machinery worth millions of euros, an environmental disaster or, in the worst case, a threat to human health and life.
📚 Read the complete guide: OT/ICS Security: Bezpieczeństwo systemów OT/ICS - różnice z IT, zagrożenia, praktyki
Why are security priorities different in the OT world (availability, integrity) than in IT (confidentiality)?
The classic security triad in the IT world is CIA: Confidentiality, Integrity, Availability. This means that the most important thing is to protect data from unauthorized access, then ensure its integrity, and finally availability.
In the OT world, this pyramid is turned upside down, and there is often an additional, overarching element at the top: physical security (Safety). The triad of priorities for OT is as follows:
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Availability (Availability): An absolute priority. Every second of unplanned downtime of a production line or power grid is a huge financial loss and operational risk. OT systems must operate 24/7/365 without any interruptions.
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Integrity: Extremely important. Data sent by control systems (e.g., sensor readings, commands for valves) must be accurate and unaltered. A false temperature reading in a chemical reactor can lead to disaster.
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Confidentiality: Usually the least important. The fact that someone can eavesdrop on what temperature a sensor is is often an acceptable risk, as long as they are not able to change that value.
This fundamental difference in priorities has huge implications for security strategy. It is unacceptable to implement mechanisms in an OT network that, in the name of confidentiality, could even momentarily disrupt availability (e.g., an overly aggressive IPS blocking unusual but legitimate traffic).
Comparing the IT and OT Worlds: Key Security Differences
| Aspect | IT (Information Technology) environment | OT (Operational Technology) environment |
|---|---|---|
| Main Priority | Confidentiality | Availability (Availability) and Physical Security (Safety) |
| Tolerance for Downtime | Medium to low (mail interruption is a problem, but rarely a disaster) | Extremely low (every second of production line downtime is a real financial loss) |
| Systems Life Cycle | Short (3-5 years). Frequent updates. | Very long (15-20+ years). Rare, complicated and risky upgrades. |
| Main Threat | Theft, modification or loss of data | Disruption or sabotage of the physical process, danger to people and the environment |
| Typical Protocols | Open, standard (TCP/IP, HTTP, SMTP) | Specialized, often obsolete and unsecure industrial protocols (Modbus, Profinet, DNP3) |
Why are traditional IT security tools, such as vulnerability scanners, dangerous for OT networks?
One of the biggest mistakes IT departments make is trying to manage an OT environment with the same tools they successfully use in the office network. This is a straight road to disaster, and active vulnerability scanners are a prime example.
In the IT world, regular proactive network scanning for open ports and vulnerabilities is a basic and essential practice. The scanner sends thousands of specially crafted packets to each device to test its response and identify vulnerabilities. Such an “aggressive” process, however, is deadly to fragile and often outdated OT systems.
PLCs, HMIs and other industrial devices often run on very simple network stacks that were not designed to handle unusual traffic. Active scanning can be interpreted by them as an error or an attack, which can lead them to hang up, reboot or go into an emergency state. At best, this will result in temporary downtime. At worst, stopping the controller in the middle of a critical process could lead to physical damage to the machine or danger to operators. Therefore, in OT networks, monitoring must be 100% passive.
What is IT/OT convergence and what new risks does it bring?
IT/OT convergence is a process of blurring the traditional boundary and increasing integration between office and industrial systems. It is driven by business needs: engineers want remote access to machines, management wants real-time production performance data, and ERP systems need to communicate with production management systems (MES).
While logical and necessary, this convergence creates a huge new attack surface. It opens up digital “highways” from the relatively dangerous and exposed IT world to the previously isolated and vulnerable OT world. Threats that were once a concern only for the IT department can now directly affect the production process.
The biggest risk is the spread of malware. Ransomware that infects a laptop in the office can penetrate the production network through newly opened network connections and encrypt SCADA servers or engineering stations, paralyzing the entire factory. An attacker who gains access to the IT network through phishing can use it as a beachhead to launch an attack on control systems. Managing this convergence securely is the biggest challenge for industrial companies today.
What is the Purdue model and how does it help segment industrial networks?
The Purdue model (Purdue Enterprise Reference Architecture) is a well-established, hierarchical conceptual model that has been used for years to design secure and reliable network architectures in industrial control environments. It divides the entire infrastructure into logical levels (0 to 5), grouping systems with similar function and security requirements.
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Levels 0, 1, 2 (Industrial Zone/OT): This is the heart of the operation. Level 0 is physical processes (motors, valves). Level 1 is the basic control equipment (PLCs, sensors). Level 2 is supervisory and control systems (HMI, SCADA).
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Level 3 (Manufacturing Zone): Production support systems such as data historian servers, MES systems.
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Demilitarized Zone (DMZ, Level 3.5): This is the key security buffer that separates the OT world from the IT world. This is where you place servers that need to be accessible from both networks (e.g., proxy server, terminal server).
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Levels 4, 5 (Corporate/IT Zone): This is a classic office network with business servers (ERP), workstations and Internet access.
The main principle of the Purdue model is strict segmentation and control of communication between levels. Traffic between the IT zone and the OT zone should be allowed only through the DMZ and strictly controlled by firewalls. Direct communication from a workstation in the office to a PLC on the production line is absolutely forbidden. Implementing an architecture based on this model is a fundamental step in securing an industrial environment.
How does nFlo help industrial companies secure their critical OT environments?
At nFlo, we have unique competencies that combine deep IT cybersecurity expertise with an understanding of the specifics and sensitivities of operational technology (OT) environments. We understand that in this world, priorities are different and a “copy-paste” approach from IT is not acceptable. We act as a partner to help build a bridge between IT and automation teams, creating a consistent and secure security strategy.
Our services begin with a specialized OT security audit. We assess industrial network architecture for compliance with the Purdue model, identify unsecured connections between IT and OT, and analyze risks. Crucially, we only apply 100% passive analysis methods to OT environments, which do not interfere with system operations and pose no risk of downtime.
We design and implement secure, segmented network architectures, using next-generation firewalls (NGFWs) to create robust DMZs and tight control of communications. We also deploy specialized platforms for passive OT network monitoring, which, like NDR systems in the IT world, can detect anomalies and threats by understanding the specifics of industrial protocols. We also help companies comply with the requirements of the NIS2 directive, which imposes strict new OT cybersecurity obligations on many industrial players.
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