OT Security: Securing Industrial Control Systems

OT (Operational Technology) Security protects industrial control systems (ICS), SCADA systems, PLCs, and other operational devices that manage physical processes. Unlike IT security, OT security must prioritize availability and safety over confidentiality. According to CISA, OT attacks increased by 87% in 2025, with critical infrastructure being the primary target.

OT environments have unique constraints: legacy systems that can't be patched, 24/7 uptime requirements, safety implications of system failures, proprietary protocols (Modbus, DNP3), and 15-25 year equipment lifecycles. NIST SP 800-82 provides the foundational framework for addressing these differences. A failed OT security control can result in physical harm, environmental damage, or production shutdown-unlike IT where the impact is typically data loss.

IEC 62443 is the international standard for industrial automation and control system (IACS) security. It defines security levels (SL 1-4), zones, and conduits for network segmentation, and provides requirements for both asset owners and system integrators. The standard is increasingly required by critical infrastructure regulators worldwide.

Start with asset discovery and network visibility-most organizations don't have complete inventories of their OT assets. Then implement network segmentation between IT and OT using DMZ architecture (Purdue Model Level 3.5), deploy passive monitoring that doesn't disrupt operations, and establish OT-specific incident response procedures. This guide provides a phased roadmap.

Yes. The guide includes coverage of NCIIPC (National Critical Information Infrastructure Protection Centre) guidelines, sectoral CERT requirements (CERT-In), and India-specific regulatory frameworks for power, oil & gas, and transportation sectors. It addresses data localization requirements and indigenous technology considerations.

The guide covers OT-specific security tools including Claroty, Nozomi Networks, Dragos, and Fortinet OT Security for asset discovery and threat detection. It also addresses industrial-grade firewalls, unidirectional security gateways (data diodes), and secure remote access solutions designed for operational environments.