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NIST SP 800-53 Learning Center

SC-47 — Alternate Communications Paths

Read the official control and assessment content, then use the separately labeled Bare Metal Cyber perspective to connect the requirement to implementation, evidence, and sustained operation.

0Enhancements
1Parameters
0Baseline memberships
3Assessment methods

SC — System and Communications Protection · NIST SP 800-53 Release 5.2.0

Official NIST control content

Control statement

Establish [Organization-defined: alternate communication paths] for system operations organizational command and control.

Official NIST discussion

Discussion

An incident, whether adversarial- or nonadversarial-based, can disrupt established communications paths used for system operations and organizational command and control. Alternate communications paths reduce the risk of all communications paths being affected by the same incident. To compound the problem, the inability of organizational officials to obtain timely information about disruptions or to provide timely direction to operational elements after a communications path incident, can impact the ability of the organization to respond to such incidents in a timely manner. Establishing alternate communications paths for command and control purposes, including designating alternative decision makers if primary decision makers are unavailable and establishing the extent and limitations of their actions, can greatly facilitate the organization’s ability to continue to operate and take appropriate actions during an incident.

Official OSCAL parameters

Organization-defined parameters

These values must be resolved through the organization’s tailoring and governance process. Bracketed parameter references in the control text identify where a decision is required.

alternate communication pathsalternate communication paths for system operations and operational command and control are defined;
Original Bare Metal Cyber perspective

From control text to operational evidence

Use Alternate Communications Paths as a testable risk decision. Translate the official statement into accountable people, repeatable processes, configured technology, and evidence that demonstrates the outcome over time. In this family, pay particular attention to secure architecture, boundary protection, communications protection, cryptography, and system isolation.

Implementation workflow

  • Define the control boundary, responsible owner, inherited portions, and systems or processes in scope.
  • Resolve each organization-defined parameter before declaring the control implemented.
  • Document how the implementation satisfies every clause of the official control statement.
  • Collect evidence as a normal byproduct of operation rather than only before an assessment.
  • Review exceptions, changes, and monitoring results on a risk-based cadence.

Evidence examples

  • network and trust-boundary diagrams
  • firewall and gateway configurations
  • cryptographic configuration and key records
  • segmentation and isolation test results

Common failure patterns

  • diagrams omit cloud and third-party paths
  • encryption enabled without key governance
  • flat trust zones allow unnecessary lateral movement
  • boundary rules accumulate without owner review

Questions practitioners should ask

  • What risk decision is this control intended to support in this system?
  • Which parts are implemented locally, inherited, shared, or not applicable—and what evidence supports that decision?
  • Do the documented narrative, deployed configuration, operating process, and collected evidence agree?
  • What event or threshold requires the implementation to be reviewed or changed?
Official NIST SP 800-53A content

Assessment objectives and methods

Show the assessment objective

[Organization-defined: alternate communication paths] are established for system operations and operational command and control.

Examine

  • System and communications protection policy
  • procedures addressing communication paths
  • system design documentation
  • system configuration settings and associated documentation
  • system audit records
  • system security plan
  • other relevant documents or records

Interview

  • System/network administrators
  • organizational personnel with information security responsibilities
  • system developers

Test

  • Mechanisms supporting and/or implementing alternate communication paths for system operations
Official relationships

Related controls

These relationships come from the official OSCAL catalog. They indicate useful dependencies or context, not automatic inheritance or equivalence.

Source record

Authoritative sources