CMMC Level 2 Practice 3.3.3: Review and update logged events

CMMC Level 2 Practice 3.3.3 requires you to routinely review your security event logs and update what you log based on changes in systems, threats, and operational needs. To operationalize it fast, define log sources and event types for your CUI environment, assign review ownership, run a recurring review workflow, and retain evidence that reviews occurred and resulted in concrete updates. ¹

Key takeaways:

• Treat 3.3.3 as an operational cadence: review logs, document findings, and tune what gets logged. ¹
• Evidence matters as much as tooling; keep dated review records, change tickets, and before/after logging configurations.
• Scope it to the CMMC assessment boundary that stores, processes, or transmits CUI, plus supporting security tooling. ²

“Review and update logged events” sounds simple until an assessor asks you to prove it: who reviewed, what they looked at, what changed, and whether it covers the systems in your CUI environment. CMMC Level 2 Practice 3.3.3 (mapped to NIST SP 800-171 Rev. 2 control 3.3.3) expects an operating process, not a one-time SIEM deployment. ¹

For a CCO or GRC lead, the fastest path is to make this requirement auditable. That means (1) defining what “logged events” includes for your environment, (2) setting a repeatable review and tuning cadence tied to change management and incidents, and (3) retaining crisp artifacts that show decisions and outcomes. If you do only “log review” without “update,” you usually fail the intent. If you do “update” without evidence of a review, you usually fail the assessment conversation.

This page is written to help you implement the cmmc level 2 practice 3.3.3: review and update logged events requirement as a requirement-level control: scope, procedure, roles, evidence, common pitfalls, and a practical execution plan aligned to CMMC and NIST SP 800-171 Rev. 2. ¹

Requirement: CMMC Level 2 Practice 3.3.3 (Review and update logged events)

Target keyword: cmmc level 2 practice 3.3.3: review and update logged events requirement

Plain-English interpretation

You must do two things repeatedly:

1. Review logged events (your logs and alert outputs) to confirm they are complete, useful, and support detection and investigation.
2. Update logged events by adjusting log sources, event types, filters, retention, forwarding, parsing, and alert rules when gaps or noise are identified.

This is not “someone glances at a dashboard.” The requirement expects a closed-loop cycle: review → findings → changes → validation → evidence. ¹

Regulatory text

The CMMC Level 2 practice is mapped to NIST SP 800-171 Rev. 2 requirement 3.3.3: “Review and update logged events.” ¹

What the operator must do: implement a repeatable process to (a) evaluate whether current logging is sufficient for security monitoring and investigations in your CUI environment, and (b) make and document updates to logging based on that evaluation. Tie this to your CMMC program scope and assessment expectations. ²

Who it applies to (entity + operational context)

Entities

• Defense contractors and subcontractors pursuing CMMC Level 2 certification.
• Federal contractors handling Controlled Unclassified Information (CUI) in non-federal systems. ³

Operational context (scope)

Apply 3.3.3 to:

• The CMMC assessment boundary (systems that store, process, or transmit CUI).
• Security tooling that collects, stores, or analyzes events for those systems (e.g., log collectors, SIEM, EDR consoles, identity platforms used for boundary access).
• Shared services that materially affect the boundary (for example, centralized identity, email security, or remote access). Document why each is in or out of scope for review. ²

Practical scoping rule: if an incident responder would need the logs to investigate a suspected CUI impact, include it in your review set.

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

Step 1: Define your “logged events” inventory (and make it assessable)

Create a Log Source Register for the boundary:

• Log source name, owner, system role (DC, firewall, SaaS), and boundary relationship
• Where logs are stored (local, centralized)
• What is logged (auth events, admin actions, network connections, file access where applicable)
• Forwarding path (agent, syslog, API)
• Retention and access controls
• Known gaps / constraints

Output artifact: “CUI Boundary Logging Coverage Matrix.”

Step 2: Set review triggers and a recurring review cadence

Use two review types:

• Recurring review: a scheduled review of logging coverage and quality across the boundary.
• Event-driven review: triggered by material changes such as new systems, major config changes, onboarding a third party managed service, or after an incident/near miss.

Document triggers in your logging standard and connect them to change management. The assessor will look for proof that logging updates happen when your environment changes. ¹

Step 3: Standardize what “review” means (a checklist that produces findings)

A log review for 3.3.3 should answer:

• Are critical systems still sending logs (no silent failures)?
• Are timestamps consistent and usable for correlation?
• Do logs include enough context (user, host, source IP, action, result)?
• Are there high-noise sources drowning out signal?
• Are there blind spots introduced by new services, new admin roles, or new remote access paths?
• Can you reconstruct a basic incident timeline for boundary systems from what you have?

Output artifact: a completed “Logged Events Review Checklist” with reviewer name, date, scope, and findings.

Step 4: Convert findings into updates (controlled, tracked changes)

For each finding, open a tracked work item (ticket, change record, or GRC task) and classify it:

• Coverage gap: add a missing source, enable an audit policy, add an integration.
• Quality issue: fix parsing, normalize fields, adjust time sync, tag assets.
• Noise issue: refine filters or alert logic while preserving forensic value.
• Access/control issue: tighten who can read logs, protect log integrity.

Output artifacts:

• Change tickets with approval and implementation notes
• Before/after configuration snapshots (redact secrets)
• Validation evidence (test event generated and observed end-to-end)

Step 5: Validate the update worked (don’t skip this)

Validation should be concrete:

• Generate a representative event (e.g., test login failure, test admin action).
• Confirm the event appears in the central repository with expected fields.
• Confirm alerting/detection (if applicable) behaves as designed.

Output artifact: “Logging Update Validation Record” attached to the change ticket.

Step 6: Report upward and retain evidence for assessment

Provide a short monthly/quarterly roll-up for governance:

• What was reviewed
• Key gaps found
• What was changed
• Open items and risk acceptance (if any)

This is where Daydream fits naturally: many teams can do the technical work, but they struggle to keep evidence consistent across cycles. Daydream can track the review cadence, store the checklists and change records, and map them directly to 3.3.3 so the assessor sees a clean control narrative and recurring evidence capture. ¹

Required evidence and artifacts to retain

Keep evidence that proves operation over time:

• Logging policy/standard that defines review approach and triggers
• Log Source Register / Logging Coverage Matrix for the CUI boundary
• Dated review records (checklists, meeting notes, sign-offs)
• Samples of logs from key sources (redacted) showing content and timestamps
• Change tickets and approvals for logging updates
• Before/after configuration exports or screenshots (redacted)
• Validation records showing updates took effect
• Exceptions/risk acceptances with compensating controls, if any

Evidence quality test: a third party should be able to replay your story from “review” to “update” without hallway conversations.

Common exam/audit questions and hangups

Assessors and internal auditors tend to probe:

• “Show me the last review. What systems were in scope and why?”
• “What changed in logging as a result of that review?”
• “How do you know logs aren’t silently failing from critical systems?”
• “How does this process react when you onboard a new SaaS app or third party managed service?”
• “Who has access to logs, and how do you protect log integrity?”
• “How do you confirm time synchronization and consistent timestamps across sources?”

Hangup to anticipate: teams can demonstrate log collection but cannot show the update loop with evidence.

Frequent implementation mistakes (and how to avoid them)

1. No defined boundary.
   Fix: tie the log inventory explicitly to the CUI assessment boundary and document inclusions/exclusions. ²

2. Review meetings without artifacts.
   Fix: require a completed checklist and a short findings log every time, even if “no changes needed.”

3. Updates happen ad hoc with no traceability.
   Fix: route tuning through tickets, even for “small” changes like filters and alert thresholds.

4. Only the SIEM is reviewed, not the sources.
   Fix: confirm endpoint/network/identity sources still generate the needed events; the SIEM cannot ingest what isn’t produced.

5. Noise reduction breaks forensics.
   Fix: filter at alerting/query level first; be cautious about dropping raw events unless you document the rationale and alternatives.

Enforcement context and risk implications

No public enforcement cases were provided in the supplied source catalog for this specific practice, so you should treat the risk primarily as assessment failure and contractual impact rather than a citation-based penalty discussion. ³

Operationally, weak implementation increases:

• Mean time to detect and investigate boundary-relevant incidents
• Inability to prove what happened during an event affecting CUI systems
• Assessment friction when you cannot show repeatable operation and evidence

Practical execution plan (30/60/90-day)

First 30 days (stand up the control)

• Define boundary log sources and build the Log Source Register.
• Publish a one-page procedure: scope, roles, review checklist, triggers, ticketing requirement.
• Run your first logged events review and produce findings with at least one completed update ticket.

By 60 days (make it repeatable)

• Integrate review triggers into change management (new systems and major changes require logging review sign-off).
• Standardize evidence storage (single repository, consistent naming).
• Add validation steps to every logging update ticket.

By 90 days (make it assessment-ready)

• Produce a management roll-up from multiple review cycles.
• Run a tabletop: pick a recent change or incident scenario and confirm logs support timeline reconstruction.
• Tighten access controls to logs and document who can read/modify configurations and how changes are approved. ¹

Frequently Asked Questions

What counts as an “update” for 3.3.3?

Any documented change to improve logging coverage, quality, or usefulness counts, such as adding a new log source, enabling audit settings, fixing parsing, or adjusting filters with validation evidence. The key is traceability from a review finding to a controlled change. ¹

Do we need a SIEM to meet this requirement?

The requirement is outcome-based: you must review and update logged events. A SIEM often simplifies centralization and evidence, but you can meet the practice with other centralized logging approaches if reviews and updates are documented and effective. ¹

How do we scope reviews in a hybrid environment (on-prem + cloud)?

Anchor the scope to the CUI assessment boundary and the services that provide security-relevant events for it (identity, endpoints, networks, key SaaS). Document inclusions/exclusions in your Log Source Register. ²

What evidence is most persuasive to an assessor?

Dated review records plus linked change tickets that show what you changed, who approved it, and proof the update worked (before/after configs and validation logs). A clean evidence chain beats large volumes of raw logs. ¹

We reviewed logs and found nothing to change. How do we prove compliance?

Keep the completed review checklist, a short statement of scope and results, and any health checks showing key sources still forward logs. “No changes” is acceptable if the review is real and evidenced. ¹

How does Daydream help without replacing our security tools?

Daydream can act as the control system of record: schedule and assign reviews, store checklists and tickets, and map recurring evidence directly to 3.3.3 for assessment readiness. Your SIEM/EDR still does collection and detection; Daydream keeps the compliance trail consistent. ²

Footnotes

1. NIST SP 800-171 Rev. 2

2. DoD CMMC Program Guidance

3. 32 CFR Part 170