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SC-3(4) SC · System and Communications Protection

Module Coupling and Cohesiveness

LOW MODERATE HIGH
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Requirements NIST SOURCE

Implement security functions as largely independent modules that maximize internal cohesiveness within modules and minimize coupling between modules.

Discussion (NIST Supplemental Guidance)

The reduction of inter-module interactions helps to constrain security functions and manage complexity. The concepts of coupling and cohesion are important with respect to modularity in software design. Coupling refers to the dependencies that one module has on other modules. Cohesion refers to the relationship between functions within a module. Best practices in software engineering and systems security engineering rely on layering, minimization, and modular decomposition to reduce and manage complexity. This produces software modules that are highly cohesive and loosely coupled.

Implementation Guidance

Engineering Interpretation

Original engineering commentary written for this explorer — not NIST source text and not authoritative guidance.

No engineering interpretation has been authored for SC-3(4) yet. This section is architected to receive it — see the Requirements and Assessment sections above for the authoritative NIST source content in the meantime.

Assessment

NIST SP 800-53A REV 5.2.0

Assessment Objectives

  1. security functions are implemented as largely independent modules that maximize internal cohesiveness within modules;
  2. security functions are implemented as largely independent modules that minimize coupling between modules.

Examine

[SELECT FROM: System and communications protection policy; procedures addressing security function isolation; system design documentation; system configuration settings and associated documentation; system audit records; system security plan; other relevant documents or records].

Interview

[SELECT FROM: System/network administrators; organizational personnel with information security responsibilities].

Test

[SELECT FROM: Organizational processes for maximizing internal cohesiveness within modules and minimizing coupling between modules; mechanisms supporting and/or implementing security functions as independent modules].

Overlays

Showing the OT/ICS overlay for the parent control SC-3 — see the SC-3(4) entries within each baseline below.

OT/ICS Overlay SP 800-82r3

NIST SP 800-82r3 Appendix F, Table 22. Blank baseline means the control/control enhancement is not selected in that initial OT baseline.

LOW

Not applicable at this tier.

MODERATE

Not applicable at this tier.

HIGH

  • Base control: Included (matches standard baseline)

STIGs & CCIs

No STIG checks or CCI mappings are currently loaded for SC-3(4). This section is architected to display, per product: STIG ID, Finding ID, Severity, Title, Description, Check, Fix, CCI, and NIST control mapping — but nothing is populated here until a real DISA STIG/CCI dataset is ingested.

Learn more about STIG/CCI integration →

Evidence

Potential Evidence — Derived

Categorized from the SP 800-53A "Examine"/"Test" artifact list above by keyword — not an authoritative NIST evidence list.

Policy

  • System and communications protection policy
  • system security plan

Configuration

  • system design documentation
  • system configuration settings and associated documentation

Testing

  • Organizational processes for maximizing internal cohesiveness within modules and minimizing coupling between modules
  • mechanisms supporting and/or implementing security functions as independent modules

Other Records

  • procedures addressing security function isolation
  • system audit records
  • other relevant documents or records