NIST 800-53 REV 5 • SYSTEM AND INFORMATION INTEGRITY
SI-21 — Information Refresh
Refresh {{ insert: param, si-21_odp.01 }} at {{ insert: param, si-21_odp.02 }} or generate the information on demand and delete the information when no longer needed.
CMMC Practice Mapping
No direct CMMC mapping
NIST 800-171 Mapping
No direct NIST 800-171 mapping
Related Controls
Supplemental 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.
Practitioner Notes
Periodically refresh information from authoritative sources to ensure your systems are working with current, accurate data rather than stale copies.
Example 1: Configure your Active Directory to refresh group memberships and access rights from your HR system daily. When HR records show an employee has transferred departments, the access changes propagate to AD automatically, ensuring access rights stay current.
Example 2: Refresh your threat intelligence feeds at least every 24 hours. Stale IOCs (indicators of compromise) can lead to missed detections or false positives. Configure your SIEM and firewall to automatically pull updated threat feeds on a regular schedule.