au-4-audit-log-storage-capacity

name	AU-4_audit-log-storage-capacity
description	Allocate audit log storage capacity to accommodate [organization-defined].
category	information-gathering
version	5.2.0
author	cyberstrike-official
tags	["nist","sp800-53","rev5","au-4","au"]
tech_stack	["aws","azure","gcp","linux","windows"]
cwe_ids	["CWE-778"]
chains_with	["AU-2","AU-5","AU-6","AU-7","AU-9","AU-11","AU-12","AU-14","SI-4"]
prerequisites	[]
severity_boost	{"AU-2":"Chain with AU-2 for comprehensive security coverage","AU-5":"Chain with AU-5 for comprehensive security coverage","AU-6":"Chain with AU-6 for comprehensive security coverage"}

AU-4 Audit Log Storage Capacity

High-Level Description

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

Organizations consider the types of audit logging to be performed and the audit log processing requirements when allocating audit log storage capacity. Allocating sufficient audit log storage capacity reduces the likelihood of such capacity being exceeded and resulting in the potential loss or reduction of audit logging capability.

What to Check

• Verify AU-4 Audit Log Storage Capacity is documented in SSP
• Confirm control is operating effectively
• Review evidence of continuous monitoring for AU-4

How to Test

Step 1: Review Documentation

Examine the System Security Plan (SSP) and related artifacts for AU-4 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

Tool	Purpose	Usage
cloud-audit-mcp	Check logging configuration	cloud_audit_logging
AWS CLI	Review CloudTrail/CloudWatch	aws cloudtrail describe-trails

Remediation Guide

Control Statement

Allocate audit log storage capacity to accommodate [organization-defined].

Implementation Guidance

Organizations consider the types of audit logging to be performed and the audit log processing requirements when allocating audit log storage capacity. Allocating sufficient audit log storage capacity reduces the likelihood of such capacity being exceeded and resulting in the potential loss or reduction of audit logging capability.

Risk Assessment

Finding	Severity