CA-2(3)_leveraging-results-from-external-organizations

CA-2(3) Leveraging Results from External Organizations

Enhancement of: CA-2

High-Level Description

Family: Assessment, Authorization, and Monitoring (CA) Framework: NIST SP 800-53 Rev 5

Organizations may rely on control assessments of organizational systems by other (external) organizations. Using such assessments and reusing existing assessment evidence can decrease the time and resources required for assessments by limiting the independent assessment activities that organizations need to perform. The factors that organizations consider in determining whether to accept assessment results from external organizations can vary. Such factors include the organization’s past experience with the organization that conducted the assessment, the reputation of the assessment organization, the level of detail of supporting assessment evidence provided, and mandates imposed by applicable laws, executive orders, directives, regulations, policies, standards, and guidelines. Accredited testing laboratories that support the Common Criteria Program ISO 15408-1 , the NIST Cryptographic Module Validation Program (CMVP), or the NIST Cryptographic Algorithm Validation Program (CAVP) can provide independent assessment results that organizations can leverage.

What to Check

• Verify CA-2(3) Leveraging Results from External Organizations is documented in SSP
• Confirm control is operating effectively
• Review evidence of continuous monitoring for CA-2(3)
• Verify enhancement builds upon base control CA-2

How to Test

Step 1: Review Documentation

Examine the System Security Plan (SSP) and related artifacts for CA-2(3) implementation details. Verify the organization has documented how this control is satisfied.

Step 2: Validate Implementation

# For cloud environments, use cloud-audit-mcp tools
# For on-premises, review system configurations directly

# Example: Check if account management policies exist
grep -r "account.management\|access.control" /etc/security/ 2>/dev/null

Step 3: Test Operating Effectiveness

Verify the control is actively functioning, not just documented. Check logs, configurations, and operational evidence.

Tools

Remediation Guide

Control Statement

Leverage the results of control assessments performed by [organization-defined] on [organization-defined] when the assessment meets [organization-defined].

Implementation Guidance

Organizations may rely on control assessments of organizational systems by other (external) organizations. Using such assessments and reusing existing assessment evidence can decrease the time and resources required for assessments by limiting the independent assessment activities that organizations need to perform. The factors that organizations consider in determining whether to accept assessment results from external organizations can vary. Such factors include the organization’s past experience with the organization that conducted the assessment, the reputation of the assessment organization, the level of detail of supporting assessment evidence provided, and mandates imposed by applicable laws, executive orders, directives, regulations, policies, standards, and guidelines. Accredited testing laboratories that support the Common Criteria Program ISO 15408-1 , the NIST Cryptographic Module Validation Program (CMVP), or the NIST Cryptographic Algorithm Validation Program (CAVP) can provide independent assessment results that organizations can leverage.

Risk Assessment

CWE Categories

References

• NIST SP 800-53 Rev 5 - CA-2(3)
• NIST SP 800-53A Rev 5 (Assessment Procedures)
• NIST SP 800-53 Rev 5 Full Catalog

Checklist

• Control documented in SSP
• Implementation evidence collected
• Operating effectiveness validated
• Continuous monitoring in place
• Related controls (SA-4) reviewed