AU-5(3)_configurable-traffic-volume-thresholds

AU-5(3) Configurable Traffic Volume Thresholds

Enhancement of: AU-5

High-Level Description

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

Organizations have the capability to reject or delay the processing of network communications traffic if audit logging information about such traffic is determined to exceed the storage capacity of the system audit logging function. The rejection or delay response is triggered by the established organizational traffic volume thresholds that can be adjusted based on changes to audit log storage capacity.

What to Check

• Verify AU-5(3) Configurable Traffic Volume Thresholds is documented in SSP
• Confirm control is operating effectively
• Review evidence of continuous monitoring for AU-5(3)
• 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(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

Enforce configurable network communications traffic volume thresholds reflecting limits on audit log storage capacity and [organization-defined] network traffic above those thresholds.

Implementation Guidance

Organizations have the capability to reject or delay the processing of network communications traffic if audit logging information about such traffic is determined to exceed the storage capacity of the system audit logging function. The rejection or delay response is triggered by the established organizational traffic volume thresholds that can be adjusted based on changes to audit log storage capacity.

Risk Assessment

CWE Categories

References

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