CMMC Level 2 Practice 3.3.1: Create and retain system audit logs and records to the extent needed to enable the

To meet CMMC Level 2 Practice 3.3.1, you must generate audit logs for in-scope systems and retain those records long enough, and with enough detail, to support detection, investigation, response, and compliance validation for CUI-handling environments. Operationally, that means defining required events, centralizing collection, protecting log integrity, and proving logging works through repeatable evidence.

Key takeaways:

• Scope first: identify which systems handle CUI and must produce/retain audit logs ¹.
• “To the extent needed” means logs must support monitoring and incident investigation, not just exist ¹.
• Assessors look for ongoing operation: configurations, samples, retention settings, and review records ².

CMMC Level 2 Practice 3.3.1 is easy to misunderstand because it sounds like a simple “turn logging on” requirement. In assessments, teams fail it for a different reason: they can’t show that logs are complete enough, protected enough, and retained long enough to support security outcomes in the CUI boundary. The practice is mapped to NIST SP 800-171 Rev. 2 control 3.3.1, and sits in the Audit and Accountability family, which assessors treat as foundational for incident response, access control validation, and forensics ¹.

For a CCO, GRC lead, or compliance officer, the fastest path is to treat 3.3.1 as a short operational standard: define which event types must be logged, define where logs go, define how long they are kept, define who can change logging settings, and define how you prove all of that every month. Your goal is not “a SIEM.” Your goal is defensible audit logging across endpoints, servers, identity, network, and cloud services that touch CUI, with retention and integrity controls that stand up under CMMC assessment expectations ³.

Regulatory text

Requirement (mapped): “CMMC Level 2 practice mapped to NIST SP 800-171 Rev. 2 requirement 3.3.1 (Create and retain system audit logs and records to the extent needed to enable the).” ⁴

Operator meaning: you must (1) create audit logs/records for systems in scope for CMMC Level 2, and (2) retain them at a level of detail and for a duration that supports your security operations. “To the extent needed” is a scoping and sufficiency test: can you reconstruct key events, determine what happened, and support monitoring and investigation using retained logs?

Plain-English interpretation

You pass 3.3.1 when you can answer, with evidence:

• What systems generate audit logs in the CUI boundary?
• What security-relevant events are captured (logon/logoff, privilege use, account changes, policy changes, object access where applicable, admin actions)?
• Where do those logs go (central storage/SIEM/log server), and who has access?
• How is log integrity protected (prevent tampering, detect changes, restrict admin rights)?
• How long are logs retained, and how do you show retention is actually occurring?

If your environment could suffer a security incident and you would have no usable records to investigate it, your logging is not “to the extent needed” even if logging is technically enabled.

Who it applies to

Entity scope

• Defense contractors and subcontractors that process, store, or transmit CUI and are pursuing or maintaining CMMC Level 2 compliance ⁵.

Operational scope (what systems are “in”)

Apply 3.3.1 to the CUI boundary and supporting services, including:

• Identity systems (directory services, SSO/IdP, MFA)
• Endpoints and servers used to access or process CUI
• Network/security infrastructure supporting the boundary (firewalls, VPN, EDR, IDS where present)
• Cloud services hosting CUI or providing security control plane logs (SaaS/IaaS/PaaS audit trails)
• Key admin workstations used to manage the environment

A common assessment issue: logging is strong in one layer (for example, firewall logs) but absent where it matters most (identity, endpoints, admin actions).

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

Step 1: Define the audit logging standard for the CUI boundary

Create a short “Audit Logging Standard” that states:

• In-scope systems and log sources (by category, then by system list)
• Required event categories (authentication, authorization, privilege changes, admin actions, system changes, security events)
• Time synchronization requirement for log correlation
• Minimum retention requirement you choose, plus rationale tied to detection/investigation needs
• Storage location(s) and access control rules
• Integrity expectations (write-once storage, immutability features, restricted delete rights, alerting on logging disabled)

Keep it tight. Assessors want clarity and traceability to operations ³.

Step 2: Inventory log sources and map them to the boundary

Build a log source register with:

• System name, owner, environment, whether it’s in the CUI boundary
• Logging mechanism (agent, syslog, native audit logs, cloud audit service)
• Where logs are forwarded and how you confirm forwarding
• Administrative roles that can change logging settings

This register becomes your control “map” and prevents silent gaps after system changes.

Step 3: Turn on the right logs, not just any logs

For each log source, confirm you capture security-relevant events:

• Identity: successful/failed authentication, MFA challenges, admin role changes, account creation/deletion, password resets
• Endpoints/servers: local admin group changes, service installs, security tool status, process execution signals where your tooling supports it
• Network: VPN connect/disconnect, firewall allow/deny events relevant to boundary ingress/egress, DNS where monitored
• Cloud/SaaS: admin console actions, data access events where available, API token creation, audit configuration changes

Document the configuration state with screenshots or exported configs. “We log things” is not evidence.

Step 4: Centralize collection and protect integrity

Centralize logs to reduce the chance that an attacker deletes local evidence or that logs roll over. Your options include:

• SIEM
• Central log server
• Cloud-native log retention service with immutability controls

Control points assessors probe:

• Who can delete logs?
• Who can disable logging?
• Do admins have separate accounts for daily work vs privileged log admin?
• Are logs protected from modification?

Implement role-based access, restrict deletion, and monitor for log pipeline failures ¹.

Step 5: Set retention and prove it works

Pick a retention period that matches your operational reality (investigation window, contract expectations, internal risk decisions). Then implement it in:

• SIEM/index lifecycle policies
• Cloud audit log retention settings
• Log server storage policies and backups

Evidence should show retention is configured and effective, not aspirational.

Step 6: Operationalize recurring evidence capture (the part most teams miss)

Create a recurring control procedure:

• Monthly (or per your cadence): confirm top log sources are still forwarding; export a short sample report; review alerts for logging disabled; capture screenshots of retention settings
• After changes: ensure new systems in the boundary are onboarded to logging before production use
• During incidents: preserve relevant logs as part of incident handling

This is where tooling like Daydream fits naturally: map 3.3.1 to a defined control, assign owners, and drive recurring evidence collection so you can prove operating effectiveness without rebuilding the story every assessment cycle.

Required evidence and artifacts to retain

Keep evidence aligned to what an assessor can verify quickly:

Policies / standards

• Audit Logging Standard for the CUI boundary (event categories, retention, protection, roles)
• Logging and monitoring procedures (how you review, respond to failures)

Technical artifacts

• Log source register (inventory + scope mapping)
• Configuration exports or screenshots showing:
  • Audit settings enabled (OS, IdP, SaaS, firewall/VPN, EDR)
  • Central forwarding configured and active
  • Retention settings (SIEM retention policy, cloud audit retention)
  • Access controls to logs (RBAC groups, admin roles)
• Time synchronization configuration evidence (NTP settings) to support correlation

Operational records

• Periodic checks that logs are flowing (ticket, checklist, SIEM health report)
• Samples of logs for specific event types (failed logons, admin role changes)
• Change tickets showing logging onboarding for new systems
• Incident records showing log preservation steps when relevant

Common exam/audit questions and hangups

Assessors and internal auditors often ask:

• “Show me which systems in your CUI boundary generate audit logs.” Expect to present your boundary diagram and log source register ².
• “Show me that logs are retained and cannot be easily altered or deleted.” Bring retention configuration plus access control evidence.
• “What happens if a log source stops forwarding?” Have a documented detection method (health alerts) and remediation workflow.
• “Can privileged admins change audit policy?” If yes, show separation of duties, change control, and review.
• “Provide examples of logs for authentication, privilege changes, and administrative actions.” Have pre-prepared samples.

Hangups:

• Logs exist locally but are not centralized, so retention is inconsistent.
• Cloud audit logs are not enabled by default, or retention is minimal.
• No one owns log onboarding for new systems.

Frequent implementation mistakes (and how to avoid them)

Mistake	Why it fails 3.3.1	Avoid it by
Treating 3.3.1 as “buy a SIEM”	Tool purchase doesn’t prove coverage or retention	Start with scope, event list, and evidence plan 1.
Logging only perimeter devices	You miss identity/admin actions where most investigations start	Prioritize IdP/directory, endpoints, admin consoles first.
No proof of retention	Assessors validate retention settings and actual stored data	Keep screenshots/config exports and dated log samples.
Everyone can access/delete logs	Integrity risk; weak evidentiary value	Restrict roles, remove delete rights, monitor changes.
No ongoing checks	Logging silently breaks after changes	Schedule recurring health checks and retain proof.

Enforcement context and risk implications

CMMC is implemented through DoD program requirements, and Level 2 assessments focus heavily on whether controls are implemented and operating as stated ⁶. For 3.3.1, the practical risk is straightforward: without usable logs, you cannot investigate suspicious access to CUI, validate who did what, or support incident response and reporting decisions. That turns a containable event into an open-ended exposure because you can’t establish scope.

Practical 30/60/90-day execution plan

First 30 days (establish control design and scope)

• Confirm the CUI boundary and list in-scope systems and services ¹.
• Draft and approve the Audit Logging Standard (events, sources, retention approach, access rules).
• Build the log source register; identify current gaps.
• Enable/verify logging for identity and admin consoles first; capture initial configuration evidence.

Next 60 days (implement centralized collection and retention)

• Centralize log forwarding for the highest-risk sources (identity, endpoints/servers, VPN/firewall, cloud audit logs).
• Implement access controls and separation for log administration.
• Configure retention in the central platform; test retrieval for investigation use cases.
• Create a “logging health” alerting and ticket workflow for forwarding failures.

By 90 days (operate and produce assessment-ready evidence)

• Run recurring checks and retain the records (health reports, samples, review sign-offs).
• Perform a tabletop investigation drill: pick a scenario (suspicious admin login) and show you can reconstruct the timeline from logs.
• Close remaining log source gaps and formalize onboarding steps for new systems.
• In Daydream, attach all artifacts to the 3.3.1 control record and schedule recurring evidence tasks so the evidence stays current.

Frequently Asked Questions

What does “to the extent needed” mean for log retention under 3.3.1?

It means you decide and document how much logging and retention you need to support monitoring and investigations in your CUI boundary, then implement it and prove it works ¹. Assessors expect a rationale tied to operational use, not an arbitrary setting.

Do we need a SIEM to pass CMMC Level 2 Practice 3.3.1?

No specific tool is required ¹. You do need reliable log creation and retention with protected access and evidence that logs are available when needed.

Are cloud services in scope for 3.3.1?

If a cloud service processes, stores, transmits CUI, or provides identity/admin control for the boundary, its audit logs are in scope ¹. Enable and retain cloud audit trails and keep proof of configuration.

What evidence is most persuasive in a CMMC assessment for 3.3.1?

A log source register, configuration exports/screenshots for key systems, retention settings, and dated samples showing logs exist and can be retrieved. Add recurring operational records that show you detect forwarding failures and address them ².

How do we handle third-party managed IT or SOC providers for logging?

Treat them as a third party supporting a control in your CUI boundary. Require contractual commitments for log collection, retention, access controls, and timely delivery of evidence artifacts you can present to an assessor.

What if we have multiple enclaves or segmented CUI environments?

Apply the same 3.3.1 logic per enclave: define sources, event categories, retention, and evidence per boundary. Centralized logging can span enclaves, but your documentation must show coverage for each boundary.

Footnotes

1. NIST SP 800-171 Rev. 2

2. DoD CMMC Program Guidance

3. DoD CMMC Program Guidance; NIST SP 800-171 Rev. 2

4. NIST SP 800-171 Rev. 2; DoD CMMC Program Guidance; 32 CFR Part 170

5. 32 CFR Part 170; DoD CMMC Program Guidance

6. DoD CMMC Program Guidance; 32 CFR Part 170