AU-5(1)_storage-capacity-warning

AU-5(1) Storage Capacity Warning

Enhancement of: AU-5

High-Level Description

Family: Audit and Accountability (AU) Framework: NIST SP 800-53 Rev 5

Organizations may have multiple audit log storage repositories distributed across multiple system components with each repository having different storage volume capacities.

What to Check

• Verify AU-5(1) Storage Capacity Warning is documented in SSP
• Confirm control is operating effectively
• Review evidence of continuous monitoring for AU-5(1)
• Verify enhancement builds upon base control AU-5

How to Test

Step 1: Review Documentation

Examine the System Security Plan (SSP) and related artifacts for AU-5(1) 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

Provide a warning to [organization-defined] within [organization-defined] when allocated audit log storage volume reaches [organization-defined] of repository maximum audit log storage capacity.

Implementation Guidance

Organizations may have multiple audit log storage repositories distributed across multiple system components with each repository having different storage volume capacities.

Risk Assessment

CWE Categories

References

• NIST SP 800-53 Rev 5 - AU-5(1)
• 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 (none) reviewed