Imported from node011/Bounty-Reaper (.bountyreper/skill/NIST/SP800-53_rev5/SI_system-and-information-integrity/SI-4(24)_indicators-of-compromise/SKILL.md). Install upstream with npx skills add node011/Bounty-Reaper --skill SI-4(24)_indicators-of-compromise. Copyright stays with the author.

SI-4(24) Indicators of Compromise

Enhancement of: SI-4

High-Level Description

Family: System and Information Integrity (SI) Framework: NIST SP 800-53 Rev 5

Indicators of compromise (IOC) are forensic artifacts from intrusions that are identified on organizational systems at the host or network level. IOCs provide valuable information on systems that have been compromised. IOCs can include the creation of registry key values. IOCs for network traffic include Universal Resource Locator or protocol elements that indicate malicious code command and control servers. The rapid distribution and adoption of IOCs can improve information security by reducing the time that systems and organizations are vulnerable to the same exploit or attack. Threat indicators, signatures, tactics, techniques, procedures, and other indicators of compromise may be available via government and non-government cooperatives, including the Forum of Incident Response and Security Teams, the United States Computer Emergency Readiness Team, the Defense Industrial Base Cybersecurity Information Sharing Program, and the CERT Coordination Center.

What to Check

• Verify SI-4(24) Indicators of Compromise is documented in SSP
• Confirm control is operating effectively
• Review evidence of continuous monitoring for SI-4(24)
• Verify enhancement builds upon base control SI-4

How to Test

Step 1: Review Documentation

Examine the System Security Plan (SSP) and related artifacts for SI-4(24) 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

Discover, collect, and distribute to [organization-defined] , indicators of compromise provided by [organization-defined].

Implementation Guidance

Indicators of compromise (IOC) are forensic artifacts from intrusions that are identified on organizational systems at the host or network level. IOCs provide valuable information on systems that have been compromised. IOCs can include the creation of registry key values. IOCs for network traffic include Universal Resource Locator or protocol elements that indicate malicious code command and control servers. The rapid distribution and adoption of IOCs can improve information security by reducing the time that systems and organizations are vulnerable to the same exploit or attack. Threat indicators, signatures, tactics, techniques, procedures, and other indicators of compromise may be available via government and non-government cooperatives, including the Forum of Incident Response and Security Teams, the United States Computer Emergency Readiness Team, the Defense Industrial Base Cybersecurity Information Sharing Program, and the CERT Coordination Center.

Risk Assessment

CWE Categories

References

• NIST SP 800-53 Rev 5 - SI-4(24)
• 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 (AC-18) reviewed