Glossary · OT cybersecurity
Zone and conduit model
Also known as: Zones and conduits, Zone and conduit concept
German: Zonen-und-Conduits-Modell
In IEC 62443, the zone and conduit model is the method of partitioning an industrial automation and control system into security zones, groups of assets with common security requirements, and conduits, the controlled communication paths between them, so that each zone and conduit can be assigned a target security level and appropriate countermeasures.
- OT security
- Standards
In one sentence
The IEC 62443 zone and conduit model partitions a control system into zones with common security needs and conduits controlling traffic between them.
Example
The plant is split into zones for each production line, the safety systems, the SCADA servers and the IDMZ, with conduits through firewalls that allow only documented flows.
How it applies
- Engineering: Zones are formed from the security risk assessment, considering criticality, function, location, ownership and technology. Safety-related systems are often placed in separate zones. Each Conduit is defined with its allowed communication and protection measures.
- Commissioning: The implemented network must match the zone and conduit drawing; unplanned connections, such as a modem on a controller, silently bridge zones.
- Maintenance: New devices and connections must be assigned to a zone and conduit through change control, and the drawing kept current.
- Documentation: The zone and conduit drawing is a central security document for operators, integrators and auditors. Product documentation supports it by listing the interfaces and communication needs of a component, so that integrators can place it in the right zone and define conduits.
Security zone vs. shared safety zone
A Security zone groups assets for cybersecurity purposes. A Shared safety zone is a physical area in which people and machines work together under safety functions. Documents should not shorten either to "zone" without context.