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IEC 62443-4-2 Clause 4 – Common Component Security Constraints

ISA/IEC 62443-4-2, Clause 4 defines Common Component Security Constraints (CCSC) — rules that apply whenever you read, specify or implement the component requirements (CRs) in Clauses 5 through 15.

Think of CCSCs as cross-cutting conditions: they are not an eighth foundational requirement, but they shape every CR claim. Miss them and a component can “pass” a checklist while failing in a real Automation Solution.

Teaching note: Summaries paraphrase ISA/IEC 62443-4-2 for learning — always refer to the published text for normative wording.

Reference: ISA/IEC 62443-4-2, Clause 4
Related: Part 4-2 overview | IEC 62443-4-1 Product Security Lifecycle | IEC 62443-3-3 Foundational Requirements

Constraints in Clause 4

CCSC summaries

CCSC 1: Support of essential functions

Clause: 4.2

Summary
Component behaviour must respect the essential-function constraints described in Clause 4 of ISA/IEC 62443-3-3. Security features must not casually disable the process-critical functions the Automation Solution depends on.

CCSC 2: Compensating countermeasures

Clause: 4.3

Summary
Where a component cannot meet a CR on its own, product documentation must describe the external compensating countermeasures that the surrounding system must apply so the requirement is still met when the component is integrated.

CCSC 3: Least privilege

Clause: 4.4

Summary
Where required and appropriate, components must support least privilege: enough permission granularity and flexible mapping of permissions to roles, with individual accountability when needed. Exact granularity depends on device type and should be stated in product documentation.

CCSC 4: Software development process

Clause: 4.5

Summary
Every component type covered by Part 4-2 must be developed and supported under the secure product development processes of ISA/IEC 62443-4-1. Technical CR claims assume a real SDL behind the product.

Key takeaways