| name | SI-21_information-refresh |
| description | Refresh [organization-defined] at [organization-defined] or generate the information on demand and delete the information when no longer needed. |
| category | input-validation |
| version | 5.2.0 |
| author | cyberstrike-official |
| tags | ["nist","sp800-53","rev5","si-21","si"] |
| tech_stack | ["aws","azure","gcp","linux","windows"] |
| cwe_ids | ["CWE-20"] |
| chains_with | ["SI-14"] |
| prerequisites | [] |
| severity_boost | {"SI-14":"Chain with SI-14 for comprehensive security coverage"} |
SI-21 Information Refresh
High-Level Description
Family: System and Information Integrity (SI)
Framework: NIST SP 800-53 Rev 5
Retaining information for longer than it is needed makes it an increasingly valuable and enticing target for adversaries. Keeping information available for the minimum period of time needed to support organizational missions or business functions reduces the opportunity for adversaries to compromise, capture, and exfiltrate that information.
What to Check
How to Test
Step 1: Review Documentation
Examine the System Security Plan (SSP) and related artifacts for SI-21 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 integrity monitoring | cloud_audit_monitoring |
| AWS CLI | Review GuardDuty/Inspector | aws guardduty list-detectors |
Remediation Guide
Control Statement
Refresh [organization-defined] at [organization-defined] or generate the information on demand and delete the information when no longer needed.
Implementation Guidance
Retaining information for longer than it is needed makes it an increasingly valuable and enticing target for adversaries. Keeping information available for the minimum period of time needed to support organizational missions or business functions reduces the opportunity for adversaries to compromise, capture, and exfiltrate that information.
Risk Assessment
