CMMC Level 2 Practice 3.14.3: Monitor system security alerts and advisories and take action in response

To meet CMMC Level 2 Practice 3.14.3, you must continuously monitor credible security alerts and advisories that affect your environment (internal tool alerts and external vulnerability advisories) and document timely actions such as triage, patching, configuration changes, or compensating controls. Assessors will look for repeatable operations and evidence that alerts drive action (DoD CMMC Program Guidance; NIST SP 800-171 Rev. 2; 32 CFR Part 170).

Key takeaways:

• You need both detection (monitoring/feeds) and response (triage, decisions, remediation, verification) tied to your CUI systems.
• Evidence must show a closed loop: alert received → assessed → action taken → validated → recorded.
• Operationalize with a defined alert intake + severity model + SLAs + exception handling that maps to your SSP/POA&M.

The fastest way to operationalize the cmmc level 2 practice 3.14.3: monitor system security alerts and advisories and take action in response requirement is to treat it as a closed-loop control: you ingest alerts (from security tooling and from authoritative advisory sources), you triage them against your assets and CUI boundary, and you take and document action. The “monitor” part fails if you cannot show consistent intake and review. The “take action” part fails if you cannot show decisions, fixes, and verification.

This practice is mapped to NIST SP 800-171 Rev. 2, 3.14.3, and is assessed as part of CMMC Level 2 for organizations that handle CUI for the DoD (NIST SP 800-171 Rev. 2; DoD CMMC Program Guidance; 32 CFR Part 170). For most companies, the gap is not tooling. It is operational discipline: defined ownership, documented thresholds for response, and retained evidence that an advisory resulted in a tracked outcome.

Use this page as an implementation runbook: who owns what, how to build the intake and triage workflow, what artifacts to keep, and what assessors commonly probe.

Regulatory text

Provided excerpt: “CMMC Level 2 practice mapped to NIST SP 800-171 Rev. 2 requirement 3.14.3 (Monitor system security alerts and advisories and take action in response).” (NIST SP 800-171 Rev. 2; DoD CMMC Program Guidance; 32 CFR Part 170)

Operator interpretation (what you must do)

You must:

1. Monitor security alerts generated by your environment (e.g., EDR/SIEM/IDS, cloud security alerts, authentication anomalies, endpoint health, backup failures that create security exposure).
2. Monitor security advisories from relevant authoritative sources that impact your stack (e.g., OS/app/network device vendors; key open-source packages you run; major cloud/SaaS providers in your CUI workflow).
3. Take action in response, meaning you can show a consistent process to triage, decide, remediate, and verify. Action can include patching, configuration changes, disabling vulnerable services, adding detections, isolating systems, or documented risk acceptance with compensating controls.
4. Retain evidence that the monitoring occurs and that actions are taken, especially for systems in your CUI boundary and connected supporting systems (NIST SP 800-171 Rev. 2; DoD CMMC Program Guidance).

Plain-English interpretation of the requirement

This control asks a simple question: When the world (or your tools) tells you something is wrong or newly risky, do you notice and do you do something about it?

Assessors expect you to show:

• You are not relying on “someone might see an email from a vendor.” You have defined sources and responsibilities.
• You can connect an alert/advisory to an affected asset and owner.
• Your response is consistent and recorded, not ad hoc.
• You can explain exceptions without hand-waving (NIST SP 800-171 Rev. 2; DoD CMMC Program Guidance).

Who it applies to (entity and operational context)

Applies to: Defense industrial base organizations and other federal contractors that must achieve CMMC Level 2 because they handle CUI (DoD CMMC Program Guidance; 32 CFR Part 170).

Operational scope:

• In-scope systems: endpoints, servers, network devices, identity systems, cloud workloads, and security tooling that store/process/transmit CUI, plus “supporting” systems that provide security or administrative control over them.
• In-scope alert sources: security monitoring tools you operate or contract for, plus external advisories relevant to your deployed technologies (NIST SP 800-171 Rev. 2).

Typical owners: Security Operations (internal or MSSP), IT operations, vulnerability management, and the system/component owners responsible for remediation. GRC owns mapping, evidence, and assessment readiness.

What you actually need to do (step-by-step)

1) Define the alert/advisory universe you will monitor

Create an “Alert & Advisory Sources Register” covering:

• Internal security alerts: SIEM rules, EDR detections, cloud security posture alerts, IAM suspicious sign-ins, DLP events where relevant.
• External advisories: vendor security bulletins for your OS, hypervisors, network gear, key business applications, and cloud services that touch CUI workflows.
• Third-party alerts: MSSP notifications, threat intel notifications you subscribe to, and major SaaS providers in the CUI data flow.

Control test: Pick three technologies in your CUI boundary. Can you show exactly where advisories for each are received and who reviews them?

2) Establish ownership and a triage workflow

Document a simple RACI:

• Alert intake owner (often SOC/MSSP): monitors queues and feeds, opens tickets, assigns severity.
• Triage authority (security lead): confirms relevance, scopes impact, sets required action.
• Remediation owner (IT/app owner): patches/changes config, implements mitigations.
• Approver for exceptions (risk owner/CCO/CISO delegate): signs risk acceptance with expiry and compensating controls.

Write the workflow as a one-page SOP:

1. Receive alert/advisory.
2. Validate signal (false positive check).
3. Determine applicability (is the affected product/version present? is it in the CUI boundary?).
4. Assign severity and required timeline (your internal SLA).
5. Execute remediation or compensating controls.
6. Verify (scan, config check, re-test detection).
7. Close ticket with evidence attached.

Map this SOP into your SSP control description for 3.14.3 so the assessor sees a direct line from requirement to operations (NIST SP 800-171 Rev. 2; DoD CMMC Program Guidance).

3) Implement ticketing and traceability (the “closed loop”)

You need a system of record (ticketing platform, GRC workflow, or SIEM case management) where each significant alert/advisory gets:

• Unique tracking ID
• Asset(s) affected and whether they are in the CUI boundary
• Decision (remediate, mitigate, accept risk, not applicable)
• Actions taken and by whom
• Evidence attachments
• Closure criteria

Practical rule: If it isn’t traceable, it didn’t happen for assessment purposes.

4) Build minimum viable response playbooks

Start with playbooks that cover common assessment scrutiny:

• High-confidence malware/EDR detections on CUI endpoints
• Privileged account anomalies
• Externally disclosed critical vulnerabilities in core infrastructure (VPN, identity, email gateway, hypervisor, endpoint management)
• Cloud configuration exposure alerts for storage or IAM

Each playbook should specify: triage steps, containment options, evidence to capture, and escalation path. Keep them short.

5) Prove ongoing operations with recurring review

Run a recurring review cadence that produces evidence:

• Review a sample of alerts/advisories and confirm closure quality.
• Track exceptions and overdue actions.
• Confirm coverage: new systems added to the CUI boundary must be added to advisory monitoring sources.

If you use Daydream to map controls to evidence, set 3.14.3 to automatically request and store recurring artifacts (e.g., monthly alert review export, advisory triage tickets, vulnerability remediation reports) so you can answer assessor questions without scrambling (DoD CMMC Program Guidance; NIST SP 800-171 Rev. 2).

Required evidence and artifacts to retain

Keep artifacts that show monitoring happens and action follows:

Core evidence (high value in assessments)

• Alert & Advisory Sources Register (owned, dated, reviewed)
• 3.14.3 SOP/workflow and RACI (approved version)
• Ticket samples showing end-to-end handling (intake → triage → remediation → verification)
• Evidence of remediation: patch reports, change records, configuration diffs, deployment logs
• Verification evidence: vuln scan results, control validation screenshots, re-scan outputs
• Exception records: risk acceptance with compensating controls and an expiry/review trigger
• Meeting notes or reports for recurring alert/advisory review

Evidence hygiene tips

• Ensure timestamps are visible.
• Ensure the artifact indicates scope (CUI boundary tags, system names, environment labels).
• Store evidence in a controlled repository with retention aligned to your assessment and contract needs (DoD CMMC Program Guidance; 32 CFR Part 170).

Common exam/audit questions and hangups

Assessors often probe these areas for 3.14.3 (NIST SP 800-171 Rev. 2; DoD CMMC Program Guidance):

1. “Show me what you monitor.” They will ask for your alert sources and advisory sources and how you know they cover your stack.
2. “Who looks at these, and how often?” “The SOC monitors it” is not enough without defined responsibility and evidence of review.
3. “Pick an advisory. What did you do?” They may select a recent vendor bulletin and ask for your ticket trail and remediation proof.
4. “How do you decide severity and due dates?” If it’s purely tribal knowledge, you will struggle to show repeatability.
5. “What happens when you can’t patch?” Risk acceptance must be documented, approved, bounded, and paired with compensating controls.

Frequent implementation mistakes and how to avoid them

Mistake	Why it fails	Fix
Monitoring only internal tool alerts, ignoring external advisories	You miss “newly risky” conditions until exploited	Subscribe to vendor bulletins for your core stack; track advisories to closure
Receiving advisories via shared mailbox with no owner	No accountability, no evidence of review	Assign an owner and require ticket creation for relevant advisories
Patching occurs, but no linkage to the triggering advisory	You cannot prove “take action in response”	Attach advisory link/screenshot to the change ticket; cross-reference IDs
No verification step	You cannot show the issue is actually resolved	Require re-scan/config validation before closure
Exceptions with no expiry	Risk acceptance becomes permanent	Require periodic review and documented compensating controls

Enforcement context and risk implications (without overstating)

No public enforcement cases were provided in the source catalog for this specific practice, so you should treat enforcement risk as indirect: failure of 3.14.3 increases the likelihood that known vulnerabilities or active threats persist in your environment and can undermine your CMMC Level 2 assessment outcome (DoD CMMC Program Guidance; 32 CFR Part 170). Practically, the business impact is eligibility risk for contracts that require CMMC and operational risk from delayed response to high-impact advisories.

A practical 30/60/90-day execution plan

First 30 days (stand up the closed loop)

• Define your CUI boundary and supporting systems list, then tag assets so you can determine applicability quickly (NIST SP 800-171 Rev. 2).
• Publish the Alert & Advisory Sources Register and name owners.
• Write and approve the 3.14.3 SOP + RACI.
• Configure ticket categories and required fields (asset, severity, decision, evidence, closure verification).

By 60 days (make it repeatable)

• Build core playbooks for the alert types you actually see.
• Run the workflow for real alerts/advisories and collect a clean evidence set.
• Establish exception handling with approval and review triggers.
• Implement a recurring review meeting/report that samples closed tickets and validates quality.

By 90 days (make it assessment-ready)

• Run an internal “mini-assessment” for 3.14.3: pick recent advisories and prove traceability end-to-end.
• Fix gaps: missing fields, weak verification, unclear applicability decisions.
• Map 3.14.3 evidence requirements in your GRC system so artifacts are requested and stored on a recurring basis (DoD CMMC Program Guidance; NIST SP 800-171 Rev. 2).

Frequently Asked Questions

Do we need a SIEM to satisfy CMMC Level 2 Practice 3.14.3?

The requirement is outcome-based: you must monitor alerts and advisories and take action. A SIEM can help, but assessors care more about repeatable monitoring, ownership, and evidence that alerts/advisories resulted in documented action (NIST SP 800-171 Rev. 2; DoD CMMC Program Guidance).

What counts as a “security advisory” for 3.14.3?

Treat advisories as credible notifications about vulnerabilities or security-impacting changes affecting products you run in your environment. Vendor bulletins for your OS, endpoint agents, identity provider, network devices, and cloud services that touch CUI workflows are the usual baseline (NIST SP 800-171 Rev. 2).

How do we prove “take action” if we decide an advisory is not applicable?

Document the applicability analysis in a ticket and show supporting evidence (asset inventory/version data, scope notes). “Not applicable” is acceptable when it is defensible and repeatable, not a one-line dismissal (NIST SP 800-171 Rev. 2).

What if we cannot patch quickly due to operational constraints?

Record an exception with an approved risk decision, compensating controls, and a defined review trigger. Assessors typically expect bounded exceptions with evidence that you reduced exposure while patching is pending (DoD CMMC Program Guidance; NIST SP 800-171 Rev. 2).

We outsource monitoring to an MSSP. Is that enough?

Outsourcing is fine, but accountability stays with you. Keep contracts/SOW language, notification procedures, sample alerts from the MSSP, and your internal tickets showing triage and remediation actions tied to those notifications (DoD CMMC Program Guidance; 32 CFR Part 170).

How should we map 3.14.3 into the SSP and POA&M?

In the SSP, describe the end-to-end monitoring and response workflow, tooling/feeds, roles, and evidence points. In the POA&M, track any gaps such as missing advisory sources, incomplete ticket fields, or lack of verification evidence until fully remediated (NIST SP 800-171 Rev. 2; DoD CMMC Program Guidance).