NIST SP 800-53 CA-9 Internal System Connections

Requirements NIST SOURCE

Discussion (NIST Supplemental Guidance)

Internal system connections are connections between organizational systems and separate constituent system components (i.e., connections between components that are part of the same system) including components used for system development. Intra-system connections include connections with mobile devices, notebook and desktop computers, tablets, printers, copiers, facsimile machines, scanners, sensors, and servers. Instead of authorizing each internal system connection individually, organizations can authorize internal connections for a class of system components with common characteristics and/or configurations, including printers, scanners, and copiers with a specified processing, transmission, and storage capability or smart phones and tablets with a specific baseline configuration. The continued need for an internal system connection is reviewed from the perspective of whether it provides support for organizational missions or business functions.

Enhancements NIST SOURCE

CA-9(1) Compliance Checks LOW MODERATE HIGH

Perform security and privacy compliance checks on constituent system components prior to the establishment of the internal connection.

Discussion

Compliance checks include verification of the relevant baseline configuration.

Open full page for CA-9(1) →

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 CA-9 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

system components or classes of components requiring internal connections to the system are defined;
conditions requiring termination of internal connections are defined;
frequency at which to review the continued need for each internal connection is defined;
internal connections of <CA-09_ODP[01] system components> to the system are authorized;
for each internal connection, the interface characteristics are documented;
for each internal connection, the security requirements are documented;
for each internal connection, the privacy requirements are documented;
for each internal connection, the nature of the information communicated is documented;
internal system connections are terminated after <CA-09_ODP[02] conditions>;
the continued need for each internal connection is reviewed <CA-09_ODP[03] frequency>.

Examine

[SELECT FROM: Assessment, authorization, and monitoring policy; access control policy; procedures addressing system connections; system and communications protection policy; system design documentation; system configuration settings and associated documentation; list of components or classes of components authorized as internal system connections; assessment report; system audit records; system security plan; privacy plan; other relevant documents or records].

Interview

[SELECT FROM: Organizational personnel with responsibilities for developing, implementing, or authorizing internal system connections; organizational personnel with information security and privacy responsibilities].

Test

[SELECT FROM: Mechanisms supporting internal system connections].

Overlays

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)

MODERATE

Base control: Included (matches standard baseline)

HIGH

Base control: Included (matches standard baseline)

STIGs & CCIs

No STIG checks or CCI mappings are currently loaded for CA-9. 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

Assessment, authorization, and monitoring policy
access control policy
system and communications protection policy
system security plan
privacy plan

Configuration

system design documentation
system configuration settings and associated documentation

Testing

Mechanisms supporting internal system connections

Other Records

procedures addressing system connections
list of components or classes of components authorized as internal system connections
assessment report
system audit records
other relevant documents or records