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SC-7(28) SC · System and Communications Protection

Connections to Public Networks

LOW MODERATE HIGH
1 Overlay 0 Related Controls
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Requirements NIST SOURCE

Prohibit the direct connection of [system] to a public network.

Discussion (NIST Supplemental Guidance)

A direct connection is a dedicated physical or virtual connection between two or more systems. A public network is a network accessible to the public, including the Internet and organizational extranets with public access.

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(28) 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. the system that is prohibited from directly connecting to a public network is defined;
  2. the direct connection of the <SC-07(28)_ODP system> to a public network is prohibited.

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; 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 prohibiting the direct connection of systems to an external network].

Overlays

Showing the OT/ICS overlay for the parent control SC-7 — see the SC-7(28) 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(28). 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 prohibiting the direct connection of systems to an external network

Other Records

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