NIST SP 800-171 Rev. 3 3.11.2 — Vulnerability Monitoring and Scanning

What this control requires

This control mandates monitoring and scanning the system for vulnerabilities at defined intervals and when new vulnerabilities are identified. It includes remediating vulnerabilities within specified response times and updating the system's vulnerability scanning practices to reflect newly discovered vulnerabilities. This control supports the Vulnerability Scanning capability within the Risk Assessment (3.11) family.

In plain English

This control mandates monitoring and scanning the system for vulnerabilities at defined intervals and when new vulnerabilities are identified. In practice, this means you can prove you response management-level controls on a defined cadence.

Why it matters

DoD contractors and their subcontractors must implement all 100 SP 800-171 requirements to keep CUI handling contracts. Gaps are scored against the SPRS scoring methodology; below a 110-point starting score, each unmet requirement deducts points and a below-threshold score can disqualify a bid.

This control is rated critical in the source catalogue. Treat gaps here as production incidents in the risk register, not housekeeping.

What an auditor looks for

A C3PAO conducting a CMMC Level 2 assessment uses NIST SP 800-171A objectives. They expect a System Security Plan (SSP), Plan of Action & Milestones (POA&M) for any gaps, and objective evidence (configurations, ticket records, training records) for every requirement.

Within Risk Assessment, the assessor will trace your implementation back to the catalogue reference (Requirement 3.11.2) and look for objective evidence on the latest two assessment cycles.

How to implement

Vulnerability Management

Scanners. Pair an unauthenticated scanner (Nessus / Qualys / Tenable.io) for external surface with an authenticated agent for OS/library CVEs on every host.

SLA. Document remediation SLAs by CVSS / EPSS: critical 7 days, high 30 days, medium 90 days; report monthly trend to leadership.

Containers. Scan images in CI (Trivy / Grype / Snyk Container) AND at runtime; block deploys on critical findings without exception.

Code Review Testing

Pipeline. Require at least one human reviewer plus passing CI (lint, type, unit, security scan) before merge — protected branches enforce this.

Operational checklist

• Response. Document the trigger, the owner and the cadence.
• System. Document the trigger, the owner and the cadence.
• Risk. Document the trigger, the owner and the cadence.
• Scope: management, assessment, response, code.

Evidence to collect

• Vapt Scan. vapt_scan evidence
• Infra Scan. Continuous infrastructure-posture telemetry — AWS Config, Azure Policy compliance, GCP Organisation Policy, Wiz / Prisma findings.

Pen-test and vulnerability scan reports substantiate attack-surface coverage. Focus: Vulnerability Monitoring and Scanning.

Common pitfalls

• Scans that hit only the perimeter; missing authenticated scans of OS, runtime libs and base images so most CVEs are invisible.

How it maps to other frameworks

Computed from shared tags, control component and key-operation subjects — handy when you are reconciling controls across an audit.

• NIST SP 800-53 Rev. 5 RA-5(1) — Update Tool Capability
• ISO/IEC 27001:2022 A.8.34 — Protection of information systems during audit testing
• SOC 2 (2017 TSC) CC3.3 — Fraud Risk Assessment
• BSI C5:2020 OPS-19 — Managing Vulnerabilities, Malfunctions and Errors - Penetration Tests

Related controls in NIST SP 800-171 Rev. 3

• Requirement 3.11.4 — Risk Response
• Requirement 3.12.2 — Plan of Action and Milestones
• Requirement 3.12.1 — Security Assessment
• Requirement 3.12.3 — Continuous Monitoring
• Requirement 3.6.3 — Incident Response Testing

References

• NIST Computer Security Resource Center — NIST SP 800-171 Rev. 3
• Catalogue identifier: Requirement 3.11.2

Topics: governance riskvulnerability managementcode review testingcontinuous monitoring