SI-21_information-refresh

DevOps & Security

Refresh [organization-defined] at [organization-defined] or generate the information on demand and delete the information when no longer needed.

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How to use this skill

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Prompt to paste

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Source SKILL.md: https://github.com/CyberStrikeus/CyberStrike/blob/HEAD/.cyberstrike/skill/NIST/SP800-53_rev5/SI_system-and-information-integrity/SI-21_information-refresh/SKILL.md

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Copying this prompt does not install or run the skill. Review third-party files before use. Codex skill guide

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

Verify SI-21 Information Refresh is documented in SSP
Confirm control is operating effectively
Review evidence of continuous monitoring for SI-21

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

Risk Assessment

Finding	Severity	Impact
SI-21 Information Refresh not implemented	High	System and Information Integrity
SI-21 partially implemented	Medium	Incomplete System and Information Integrity

CWE Categories

CWE ID	Title
CWE-20	Improper Input Validation

References

Checklist

Control documented in SSP
Implementation evidence collected
Operating effectiveness validated
Continuous monitoring in place
Related controls (SI-14) reviewed