Hardening commonly refers to the process of reducing the attack surface of a system, device, application, or network by configuring it in a more secure state. In industrial and manufacturing environments, hardening focuses on operational technology (OT) assets, industrial control systems (ICS), supporting IT infrastructure, and related software used in production, quality, and maintenance.
Core meaning in industrial and OT contexts
In regulated industrial environments, hardening typically includes:
- Disabling unnecessary services, ports, and protocols on controllers, servers, workstations, and network devices
- Configuring secure defaults for operating systems, PLCs, HMIs, historians, MES, and related components
- Enforcing authentication, authorization, and role-based access controls
- Applying secure network architecture concepts such as segmentation, zoning, and controlled remote access
- Configuring logging, time synchronization, and monitoring to support detection and investigation
- Setting secure parameters for encryption, key management, and certificate handling where supported
- Documenting environment assumptions and constraints that the configuration relies on
Hardening is normally performed according to internal security policies, industry guidance (for example, ICS security guidelines), or structured frameworks such as those aligned with IEC 62443. For components advertised as security-aligned, suppliers are often expected to provide hardening guides and configuration recommendations that asset owners can implement and validate.
Operational role
In day-to-day operations, hardening appears as:
- Standard build images and baseline configurations for engineering workstations, servers, and operator stations
- Commissioning and change-control steps that ensure new or modified assets are configured in line with approved security baselines
- Periodic reviews to confirm that hardening settings remain in place and compatible with production needs
- Documentation that describes intended use, security-relevant settings, and any functions that must remain disabled in validated or regulated environments
Hardening is not a one-time activity. It typically interacts with patching, system upgrades, and process changes, and it must be kept consistent with validation, qualification, and documentation requirements in regulated plants.
Common confusion
Hardening vs. patching: Hardening adjusts configuration and design to limit exposure; patching updates software or firmware to correct defects or vulnerabilities. Both are security controls but address different aspects.
Hardening vs. secure coding or design: Secure development practices aim to prevent vulnerabilities in the first place. Hardening assumes the component already exists and focuses on how it is deployed and configured.
Hardening in materials science: In metallurgy or materials engineering, hardening can refer to increasing the hardness of a material through heat treatment or work processes. In the context of industrial cybersecurity and systems, the term almost always refers to security hardening of digital or networked assets.
Link to IEC 62443-aligned documentation
For components intended to align with IEC 62443, asset owners often expect supplier documentation that explicitly covers hardening. This typically includes recommended secure configurations, assumptions about the operating environment, dependencies on other security controls, and guidance on how to maintain the hardened state over the component lifecycle.