Separate Subnets to Isolate Functions

LOW MODERATE HIGH

1 Overlay 0 Related Controls

Requirements NIST SOURCE

Implement [one of: physically; logically] separate subnetworks to isolate the following critical system components and functions: [critical system components and functions].

Discussion (NIST Supplemental Guidance)

Separating critical system components and functions from other noncritical system components and functions through separate subnetworks may be necessary to reduce susceptibility to a catastrophic or debilitating breach or compromise that results in system failure. For example, physically separating the command and control function from the in-flight entertainment function through separate subnetworks in a commercial aircraft provides an increased level of assurance in the trustworthiness of critical system functions.

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-7(29) 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

one of the following PARAMETER VALUES is selected: {physically; logically};
critical system components and functions to be isolated are defined;
subnetworks are separated <SC-07(29)_ODP[01] SELECTED PARAMETER VALUE> to isolate <SC-07(29)_ODP[02] critical system components and functions>.

Examine

[SELECT FROM: System and communications protection policy; procedures addressing boundary protection; system design documentation; system hardware and software; system architecture; system configuration settings and associated documentation; criticality analysis; system audit records; system security plan; other relevant documents or records].

Interview

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

Test

[SELECT FROM: Mechanisms separating critical system components and functions].

Overlays

Showing the OT/ICS overlay for the parent control SC-7 — see the SC-7(29) 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

Base control: Included (matches standard baseline)
Added: (28) (29)

MODERATE

Base control: Included (matches standard baseline)
Included: (3) (4) (5) (7) (8)
Added: (18) (28) (29)

HIGH

Base control: Included (matches standard baseline)
Included: (3) (4) (5) (7) (8) (18) (21)
Added: (28) (29)

STIGs & CCIs

No STIG checks or CCI mappings are currently loaded for SC-7(29). 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 architecture
system configuration settings and associated documentation

Testing

Mechanisms separating critical system components and functions

Other Records

procedures addressing boundary protection
system hardware and software
criticality analysis
system audit records
other relevant documents or records