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SC-7(3) SC · System and Communications Protection

Access Points

LOW ✓ MODERATE ✓ HIGH
1 Overlay 0 Related Controls
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Requirements NIST SOURCE

Limit the number of external network connections to the system.

Discussion (NIST Supplemental Guidance)

Limiting the number of external network connections facilitates monitoring of inbound and outbound communications traffic. The Trusted Internet Connection DHS TIC initiative is an example of a federal guideline that requires limits on the number of external network connections. Limiting the number of external network connections to the system is important during transition periods from older to newer technologies (e.g., transitioning from IPv4 to IPv6 network protocols). Such transitions may require implementing the older and newer technologies simultaneously during the transition period and thus increase the number of access points to the system.

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(3) 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 number of external network connections to the system is limited.

Examine

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

Interview

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

Test

[SELECT FROM: Mechanisms implementing boundary protection capabilities; mechanisms limiting the number of external network connections to the system].

Overlays

Showing the OT/ICS overlay for the parent control SC-7 — see the SC-7(3) 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(3). 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 and configuration documentation
  • system configuration settings and associated documentation

Testing

  • Mechanisms implementing boundary protection capabilities
  • mechanisms limiting the number of external network connections to the system

Other Records

  • procedures addressing boundary protection
  • boundary protection hardware and software
  • communications and network traffic monitoring logs
  • system audit records
  • other relevant documents or records