IEC 62443

The IEC 62443 series is organized into four general groups: general, policies and procedures, system, and component. The general group (parts 1-x) defines terminology, concepts, and models, including the foundational reference model for IACS security. The policies and procedures group (parts 2-x) addresses security management, including requirements for asset owners and integrators. The system group (parts 3-x) covers security technologies for IACS, such as system security requirements and security assurance levels. The component group (parts 4-x) specifies requirements for individual products, including embedded devices and host devices.¹

Central to IEC 62443 is the concept of zones and conduits, which segment a network into security zones with defined trust boundaries and communication conduits. Another core idea is the security level (SL), which categorizes the required robustness of a system from SL1 (protection against casual or coincidental violation) to SL4 (protection against intentional, sophisticated attacks). The standard also defines security assurance levels (SALs) for components, which are determined through a risk assessment process.²

IEC 62443 has become the de facto global benchmark for industrial cybersecurity, referenced by regulators, industry bodies, and end users across sectors such as energy, manufacturing, and transportation. It is increasingly cited in procurement contracts and used as a basis for certification schemes. The standard aligns with other frameworks like NIST SP 800-82 and the EU's NIS Directive, and its adoption is growing in critical infrastructure protection.³

While the standard is widely known for its technical controls, it also emphasizes organizational and process measures, such as the security management system and the secure development lifecycle for vendors. A lesser-known part is IEC 62443-4-2, which details technical security requirements for components, including embedded devices, host devices, and network devices. Additionally, the series includes a part on patch management (IEC 62443-2-3), which addresses the often-overlooked challenge of maintaining security updates in legacy industrial systems.⁴

IACS

Industrial Automation and Control Systems, the systems that monitor and control industrial processes.

Zone

A grouping of logical or physical assets that share common security requirements.

Conduit

A communication path that connects zones, with defined security controls.

Security Level (SL)

A measure of the robustness of a system against cyber threats, ranging from SL1 to SL4.