What Are OT and ICS?
OT (Operational Technology) is the collective term for hardware and software systems that monitor and control physical devices and industrial processes. Factory automation, energy generation and distribution, water treatment, petrochemical plants, and transportation systems are among the primary areas that fall within the scope of OT.
ICS (Industrial Control Systems) is a more specific subset of OT and consists of three core components:
- SCADA (Supervisory Control and Data Acquisition): Systems that centrally monitor and manage geographically distributed assets.
- DCS (Distributed Control Systems): Distributed systems that provide process control in large industrial facilities.
- PLC (Programmable Logic Controller): Programmable controllers that control machines on the factory floor.
Why Does It Require a Separate Security Approach?
In IT (Information Technology) security, the primary priorities are ordered as confidentiality, integrity, and availability. In OT security, these priorities are reversed: safety and availability come first.
Rebooting a corporate IT server takes a few minutes. However, halting a power distribution SCADA system or a factory production line can endanger human lives as well as result in millions of dollars in production losses.
Key differences between OT systems and IT:
- Long lifespan: Many ICS components remain in use for 15–25 years; the update window is extremely restricted.
- Real-time requirements: Even millisecond-level delays can have physical consequences.
- Limited patching capability: Applying software updates without halting production is often not possible.
- Legacy protocols: Protocols such as Modbus, DNP3, and Profibus were developed without security in mind.
Primary Threats in OT Environments
Network Convergence Risk
Historically, OT networks were physically isolated from IT networks (air-gapped). Digital transformation and Industrial IoT (IIoT) connectivity are progressively eroding this isolation. Every gateway into the OT network is a potential attack vector.
Targeted Attacks (APT)
High-profile incidents such as Stuxnet (2010), the Ukraine Power Grid attack (2015–2016), and Colonial Pipeline (2021) have demonstrated how critical infrastructure can be targeted by state-sponsored and organized cyber actors.
Ransomware
Ransomware targeting manufacturing facilities causes operational disruption, forcing organizations to pay. When production is halted, the cost per hour is extremely high.
Supply Chain Attacks
Third-party technicians who maintain OT systems or remote access connections can become attack points due to insecure configurations.
Key Controls for OT Security
Purdue Reference Model and Network Segmentation
OT environments are traditionally divided into layers according to the Purdue model: field devices, control network, operations network, and enterprise network. Firewalls and demilitarized zones (DMZ) are deployed between these layers.
OT-Focused Asset Inventory
A complete inventory of all OT assets (PLCs, RTUs, HMIs, engineering workstations) is the essential starting point for security.
Passive Network Monitoring
Passive traffic analysis tools compatible with OT protocols (such as Claroty, Dragos, and Nozomi Networks) provide network visibility without halting production.
Remote Access Control
PAM (Privileged Access Management) solutions and time-limited VPN sessions should be used for third-party access.
Patch Management Strategy
A patch management program integrated into planned maintenance processes must be established to apply patches during scheduled production downtime windows.
Critical Infrastructure Security in Turkey
In Turkey, the energy, water management, transportation, and telecommunications sectors are considered critical infrastructure. The Information Technologies and Communication Authority (BTK) and relevant ministries expect operators in these sectors to fulfill their cybersecurity obligations.
The IEC 62443 standard is the international reference framework for defining and implementing Security Levels in OT/ICS environments.
Conclusion
OT/ICS security is a critical specialized field at the intersection of the physical and digital worlds. In protecting industrial systems, the guidance of experts who understand both OT protocols and cybersecurity methodologies is of great importance. As NRC Sistem, we conduct cybersecurity assessments of your industrial environments and develop solutions for network segmentation, passive monitoring, and remote access security.