SI-19(8)_motivated-intruder

DevOps & Security

Perform a motivated intruder test on the de-identified dataset to determine if the identified data remains or if the de-identified data can be re-iden

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SI-19(8) Motivated Intruder

Enhancement of: SI-19

High-Level Description

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

A motivated intruder test is a test in which an individual or group takes a data release and specified resources and attempts to re-identify one or more individuals in the de-identified dataset. Such tests specify the amount of inside knowledge, computational resources, financial resources, data, and skills that intruders possess to conduct the tests. A motivated intruder test can determine if the de-identification is insufficient. It can also be a useful diagnostic tool to assess if de-identification is likely to be sufficient. However, the test alone cannot prove that de-identification is sufficient.

What to Check

Verify SI-19(8) Motivated Intruder is documented in SSP
Confirm control is operating effectively
Review evidence of continuous monitoring for SI-19(8)
Verify enhancement builds upon base control SI-19

How to Test

Step 1: Review Documentation

Examine the System Security Plan (SSP) and related artifacts for SI-19(8) 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

Perform a motivated intruder test on the de-identified dataset to determine if the identified data remains or if the de-identified data can be re-identified.

Implementation Guidance

Risk Assessment

Finding	Severity	Impact
SI-19(8) Motivated Intruder not implemented	High	System and Information Integrity
SI-19(8) 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 (none) reviewed