03.03.01: Event Logging

To meet the 03.03.01: event logging requirement, you must define which security-relevant events your CUI environment will log, enable logging across in-scope systems, protect those logs from tampering and loss, and produce repeatable evidence that logging is operating as designed. Your fastest path is a scoped logging standard, centralized collection, and routine log health checks tied to your SSP and POA&M. ¹

Key takeaways:

• Scope event logging to the CUI boundary, then map it to SSP statements, system components, and named owners.
• Centralize and protect logs, then prove day-to-day operation with recurring reviews and log integrity controls.
• Track gaps and tuning work in the POA&M with target dates and closure evidence before declaring the control “done.”

Event logging is one of the controls that assessors use to separate “policy-level compliance” from actual operational security. For NIST SP 800-171 Rev. 3, 03.03.01 focuses on whether you record the right events, in the right places, in a way you can rely on during an incident, investigation, or assessment. ¹

For a Compliance Officer, CCO, or GRC lead, the operational challenge is rarely turning on a log source. The hard parts are (a) defining “what is required to be logged” for your environment, (b) ensuring coverage across endpoints, identity, network, and cloud services inside the CUI boundary, and (c) retaining evidence that the control operates continuously, not only during audit week. Your SSP needs to clearly state what you log and where; your POA&M needs to show how you close gaps like missing log sources, inconsistent time synchronization, and alert fatigue. ¹

This page gives requirement-level implementation guidance you can execute quickly: a plain-English interpretation, a step-by-step build plan, evidence to retain, audit questions you should pre-answer, common failure modes, and an execution plan you can run as a control owner with IT and security operations.

Requirement: 03.03.01: Event Logging (NIST SP 800-171 Rev. 3)

Goal: Generate trustworthy logs of security-relevant events in the CUI environment so you can detect, investigate, and respond to security issues, and demonstrate control operation during assessments. ¹

## Regulatory text

“NIST SP 800-171 Rev. 3 requirement 03.03.01 (Event Logging).” ¹

Operator interpretation: You are expected to (1) decide which events matter for your risk and CUI boundary, (2) ensure systems actually record them, (3) retain and protect those records, and (4) be able to produce evidence that logging works over time. Your assessor will look for implementation detail and operating evidence, not just a policy statement. ¹

Plain-English interpretation (what “good” looks like)

You meet the 03.03.01: event logging requirement when:

• Coverage is defined: you maintain an event catalog (by platform/service) for what gets logged in the CUI boundary.
• Logging is enabled: endpoints, servers, identity, and key applications generate logs at an appropriate level.
• Logs are centralized or otherwise retrievable: you can collect and query logs without jumping across dozens of consoles.
• Logs are protected: access is limited; changes are controlled; loss is prevented with reliable retention and backup.
• Operation is provable: you can show routine checks, exceptions, and remediation tracked in the SSP/POA&M. ¹

Who it applies to

Entity types

• Federal contractors and subcontractors
• Any nonfederal organization operating systems that handle CUI (Controlled Unclassified Information) ¹

Operational context (what’s in scope)

• Systems, services, and tooling inside the CUI boundary, including:
  • Identity providers and directory services used to authenticate to CUI systems
  • Endpoints used to access CUI (workstations, virtual desktops)
  • Servers and cloud workloads that store/process/transmit CUI
  • Network/security controls (firewalls, VPN, email gateways) that protect CUI flows
  • SaaS apps approved for CUI workflows
• Third parties that host or manage in-scope infrastructure: you still need logging requirements in contracts and onboarding, plus evidence you receive and can review relevant logs (or equivalent security event evidence). ¹

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

Use this as an execution checklist you can assign to security engineering/IT with clear deliverables.

Step 1: Define the CUI logging boundary and owners

1. Confirm the CUI system boundary (what systems are in the SSP scope).
2. Assign a control owner (GRC) and technical owners (SIEM/log platform, endpoint, identity, network, cloud).
3. Create a “logging coverage matrix” with columns: system/service, log source, events captured, collection method, retention, owner.

Evidence: SSP section mapping 03.03.01 to systems and owners; boundary diagram; logging coverage matrix. ¹

Step 2: Define an event catalog with measurable criteria

Create an “events we log” standard that is testable. At minimum, cover:

• Authentication events (success/fail, MFA events, privilege escalation)
• Account and permission changes (new users, role changes, group membership)
• Administrative actions (config changes, policy changes)
• Security control events (EDR alerts, firewall denies, IDS findings)
• Data access signals for CUI repositories (read/write/delete where feasible)
• System integrity signals (service stops, agent uninstall, audit log cleared)

Write measurable criteria like “All domain-joined endpoints forward OS security logs to central collection” rather than “systems are logged.”

Evidence: Approved logging standard; event catalog; configuration baselines or control statements that reflect the catalog. ¹

Step 3: Turn on logging and centralize collection

1. Enable OS/application audit settings per your catalog.
2. Configure forwarding/collection to a centralized platform (SIEM or log management).
3. Standardize required fields: timestamp, hostname, user/account, event type, source IP where applicable.
4. Validate ingestion with a repeatable test: generate a known event and confirm it arrives in the central store.

Evidence: Screenshots or exported configs of audit policy settings; SIEM connector status; test records showing event generation and receipt. ¹

Step 4: Protect logs (access, integrity, availability)

Operational controls to implement:

• Access control: restrict who can read logs and who can administer the logging platform.
• Separation of duties: avoid giving system admins unilateral ability to delete or alter logs without oversight.
• Tamper resistance: enable immutable storage features where available; at minimum, log administrative actions on the logging platform itself.
• Retention and backup: define retention per system type; ensure retention is technically enforced and monitored.
• Time sync: standardize time sources so events correlate correctly during investigations.

Evidence: Role-based access lists; platform admin audit logs; retention settings; backup evidence; time sync configuration records. ¹

Step 5: Operate the control (review, health checks, and exceptions)

Logging fails quietly. Put recurring operations in place:

• Log source health checks (missing sources, ingestion drops, agent offline)
• Storage/retention monitoring (approaching capacity, retention drift)
• Documented exception handling (legacy systems, constrained devices)
• Periodic review sign-offs showing you checked coverage and addressed gaps

Tie exceptions and remediation work to POA&M entries with clear closure evidence.

Evidence: Recurring log health reports; ticket evidence for fixes; exception register with approvals; POA&M items with closure validation. ¹

Step 6: Map to SSP and manage gaps in the POA&M

Your SSP must answer, plainly:

• What gets logged, from which systems, and how logs are protected
• Who owns the control and what tools perform collection/review
• What evidence proves ongoing operation

For gaps, keep POA&M entries that include risk, target completion dates, and verification steps before closure. ¹

Practical note: Daydream is useful here when you want a clean line from requirement → SSP statement → system owners → recurring evidence requests → POA&M gap tracking, without relying on tribal knowledge during assessments. ¹

Required evidence and artifacts to retain

Keep artifacts that demonstrate both design and operation:

Design artifacts

• Event logging standard (policy/procedure) and event catalog
• Logging architecture diagram (sources → collectors → storage)
• SSP control narrative mapping 03.03.01 to in-scope components and owners ¹

Configuration artifacts

• Audit policy exports (OS, cloud, SaaS audit settings)
• SIEM/log platform connector configurations
• RBAC/permission exports for log systems
• Retention/immutability settings evidence ¹

Operational artifacts

• Log ingestion/health dashboards or periodic reports
• Sample log extracts showing required fields and event types
• Tickets showing remediation of failed collectors/agents
• Review attestations (who reviewed, what they checked, what changed)
• POA&M items and closure validation ¹

Common exam/audit questions and hangups

Assessors tend to probe these areas for 03.03.01: event logging requirement readiness:

• Scope clarity: “Which systems are in the CUI boundary, and are all of them logging?”
• Event completeness: “Show that authentication, admin actions, and security events are captured.”
• Log protection: “Who can delete logs? Show controls preventing tampering.”
• Operational proof: “Show recurring evidence that logging works, not a one-time screenshot.”
• Exception governance: “Which systems are not logging and why? Where is the risk acceptance documented?”
• SSP/POA&M alignment: “Does the SSP match reality, and does the POA&M show active remediation?” ¹

Frequent implementation mistakes (and how to avoid them)

1. Mistake: Treating logging as a single tool rollout.
   Fix: Manage it as a coverage program: event catalog + matrix + owners + health checks. ¹

2. Mistake: Logging enabled, but no proof it’s continuously collected.
   Fix: Keep recurring ingestion reports and tickets for dropped sources. ¹

3. Mistake: Logs stored where admins can alter or delete without trace.
   Fix: Lock down admin roles, enable audit trails for log platform actions, and require change control for retention settings. ¹

4. Mistake: SSP says “centralized logging,” but SaaS and identity logs are missing.
   Fix: Add IdP and SaaS audit feeds to the matrix and confirm ingestion with test events. ¹

5. Mistake: “We’ll fix it later” with no POA&M discipline.
   Fix: Track each missing log source as a POA&M item with an owner and closure test. ¹

Enforcement context and risk implications

No public enforcement case sources were provided for this requirement in the supplied source catalog, so this page does not list enforcement examples.

Operationally, weak event logging increases the chance you cannot prove what happened during an incident, cannot scope impact to CUI, and cannot demonstrate control operation during a NIST SP 800-171 assessment. Assessors commonly treat missing or unreliable logs as an operating effectiveness issue, even if your policy is well written. ¹

Practical 30/60/90-day execution plan

Use a staged plan you can run with IT and security owners.

First 30 days (stabilize scope and minimum viable logging)

• Confirm CUI boundary and in-scope system inventory for logging.
• Publish the event logging standard and initial event catalog.
• Stand up centralized collection for highest-value sources: identity, endpoints, and servers.
• Implement RBAC for log access and document who has admin privileges.
• Update SSP mapping for 03.03.01 and open POA&M items for missing sources. ¹

Days 31–60 (expand coverage and prove operation)

• Add remaining sources: network controls, key applications, SaaS audit logs used in CUI workflows.
• Establish log health checks and an exception process (with approvals).
• Run test cases (known events) and retain test outputs as evidence.
• Start recurring operational evidence collection (reviews, dashboards, tickets). ¹

Days 61–90 (harden and audit-proof)

• Tighten protection: verify admin activity logging on the logging platform; implement stronger immutability options where available.
• Validate retention settings and backup/restore for log stores.
• Reconcile SSP narratives with actual configs and evidence.
• Close POA&M items with documented closure validation and retest results. ¹

Frequently Asked Questions

Do we need a SIEM to satisfy the 03.03.01: event logging requirement?

NIST SP 800-171 Rev. 3 does not require a specific tool by name, but you must be able to collect, protect, and produce logs reliably for in-scope systems. A SIEM often simplifies evidence and operations because it centralizes collection and review. ¹

How do we handle SaaS products used for CUI work that have limited logging?

Document the available audit events, enable what exists, and record the limitation as an exception with risk acceptance and compensating controls. Track enhancement work or third-party commitments in the POA&M if logging is a gap. ¹

What’s the minimum evidence an assessor will accept for “operating” logging?

Keep a log coverage matrix tied to your SSP, sample log outputs from key sources, and recurring operational records such as ingestion health reports and remediation tickets. One-time screenshots are rarely persuasive on their own. ¹

Who should own event logging: security operations or GRC?

Security operations typically owns tooling and day-to-day monitoring, while GRC owns the requirement mapping, evidence plan, and POA&M governance. Assign both in the SSP so accountability is clear during assessment. ¹

How do we prove logs are protected from tampering?

Show restricted access (RBAC exports), audit trails for log platform admin actions, retention settings, and change control records for logging configuration. Where available, configure immutable storage and keep configuration evidence. ¹

We have logs everywhere, but nobody reviews them. Are we still compliant with 03.03.01?

03.03.01 is about event logging, but assessors still expect operational evidence that logging works and is managed. Add recurring health checks and documented reviews so you can prove the control operates continuously. ¹

Footnotes

1. NIST SP 800-171 Rev. 3