Event Logging

FedRAMP’s event logging requirement (NIST SP 800-53 Rev. 5 AU-2) expects you to define which security-relevant events your system can log, ensure those logs support audit and investigation needs, and coordinate with other stakeholders (security operations, incident response, privacy, HR, and the customer agency) who rely on audit data ¹. Operationalize it by publishing an event log catalog, enabling logging across the authorization boundary, and retaining evidence that logging is reviewed and acted on.

Key takeaways:

• Build and maintain an “event log catalog” that maps systems to required event types, sources, and ownership.
• Coordinate requirements with all audit-data consumers (SOC, IR, IAM, platform, customer agency) and document decisions.
• Keep operating evidence: configurations, samples of logs, review records, and tickets showing follow-up.

Event logging fails in FedRAMP programs for predictable reasons: teams turn logging on “everywhere,” drown in noise, and still miss the events assessors expect to see. AU-2 is the control that forces discipline. You must identify the types of events the system is capable of logging, select what you will actually log for audit purposes, and coordinate that decision with organizational stakeholders who need the data ¹. For a Cloud Service Provider (CSP), this is not just a SIEM configuration task. It is an authorization-boundary design decision with documentation, roles, and operating cadence.

A CCO or GRC lead needs three things to move fast: (1) a clear scope statement for what “the system” covers (your FedRAMP boundary), (2) a concrete list of event types that must be captured and where they originate, and (3) durable evidence that logs are produced, protected, and used in real operations. This page gives you requirement-level implementation guidance you can hand to engineering and security operations, then defend during 3PAO testing and continuous monitoring. For documentation packaging, align to FedRAMP-required templates and the way assessors review control descriptions and evidence ².

Regulatory text

Requirement (AU-2): “Identify the types of events that the system is capable of logging in support of the audit function and coordinate the event logging function with other organizational entities requiring audit-related information.” ¹

Operator interpretation: You must (a) enumerate audit-relevant event types and event sources within your FedRAMP authorization boundary, (b) decide which events you will collect for audit/security purposes (and at what level), and (c) document coordination with the teams and external parties who rely on that audit data ¹. Assessors will look for a coherent event logging design, not a pile of log files.

Plain-English interpretation (what AU-2 is really asking)

AU-2 is a governance-and-design control. It asks: “Do you know what you can log, did you choose a defensible set of events to log, and did you align that choice with the people who need logs to do their jobs?”

In practice, AU-2 becomes a set of decisions you must be able to explain quickly:

• Coverage: Which components inside the boundary generate logs (identity, endpoints, workloads, network, control plane, applications, databases)?
• Event types: Which actions matter (authentication, authorization, admin changes, data access, policy changes, security alerts, failures)?
• Consumers: Who uses logs (SOC, incident response, insider threat, fraud, privacy, compliance, customer agency security team)?
• Actionability: How logs feed detection, investigation, and audit evidence.

Who it applies to (entity + operational context)

Primary applicability: Cloud Service Providers operating a Cloud Service Offering (CSO) pursuing or maintaining FedRAMP authorization, and the federal agency teams involved in oversight and consumption of audit information ¹.

Operational contexts where AU-2 shows up:

• 3PAO assessment: You must show documented event types and demonstrable logging across the boundary.
• Continuous monitoring: You need repeatable proof that logging remains enabled and meaningful as systems change.
• Incident response: Your ability to reconstruct actions depends on what you decided to log and retain.
• Third-party operations: If a third party operates parts of your stack (managed SIEM, managed Kubernetes, managed database), AU-2 still expects you to define and coordinate event needs, then confirm the third party provides them.

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

Use this as an execution checklist you can assign.

Step 1: Freeze the scope (authorization boundary and log sources)

1. Pull the current boundary diagram and asset inventory used for authorization.
2. List every log-producing layer inside the boundary: identity provider, PAM, OS/auditd/EDR, application services, API gateway/WAF, load balancers, databases, object storage, KMS/HSM, CI/CD, configuration management, cloud control plane, vulnerability tooling.
3. Identify log routing paths: where logs originate, how they get to your central store/SIEM, and where they can drop.

Deliverable: Boundary-to-log-source mapping (table) suitable for SSP/control narrative ².

Step 2: Build an “Event Log Catalog” (your AU-2 backbone)

Create a controlled document (spreadsheet is fine) with these columns:

Field	What to capture	Why it matters in AU-2
System/component	e.g., IdP, API gateway, database	Defines “the system” coverage
Event type category	auth, admin, data access, policy change, security alert	Shows you identified event types 1
Specific events	e.g., login success/failure, MFA changes, role grants	Makes the requirement testable
Log field minimums	actor, target, action, result, timestamp, source IP	Enables investigation and audit reconstruction
Collection method	agent, API export, syslog, cloud-native	Shows feasibility and dependencies
Owner	platform/SRE, security ops, app team	Accountability
Retention/immutability reference	point to your retention standard	Links AU-2 decisions to retention controls
Monitoring use-case	alert, hunt, audit sampling	Shows “support of the audit function”

Tip for speed: Start with your existing SIEM source list, then formalize it into a catalog. Daydream can help centralize evidence and control narratives so the catalog stays tied to tickets, config snapshots, and assessor-ready exports without becoming a separate spreadsheet that rots.

Step 3: Coordinate with audit-data consumers (and document the coordination)

AU-2 explicitly requires coordination with “other organizational entities” that need audit-related information ¹. Make it concrete:

1. Identify stakeholders: SOC lead, IR lead, IAM owner, privacy, HR/insider threat (if applicable), product security, and the customer agency security point-of-contact.
2. Run a structured working session:
   • Which events are mandatory for investigations?
   • Which events are needed for privileged access oversight?
   • Which app/business events matter (admin feature use, export actions, key configuration toggles)?
   • What is the escalation path when critical events occur?
3. Record outcomes: accepted event list, known gaps, compensating measures, and a backlog for instrumentation.

Evidence: Meeting notes + decision log + approval in your GRC workflow.

Step 4: Implement collection and normalization (make logs defensible)

1. Turn catalog rows into engineering tasks: enable audit logs, turn on specific event types, configure log forwarding, standardize timestamps, ensure unique actor identifiers.
2. Validate end-to-end delivery:
   • Generate test events (failed logins, role changes, config edits).
   • Confirm they appear in the central log store with required fields.
3. Apply access controls: restrict who can alter logging configuration and who can access raw logs.

Evidence: Configuration exports, screenshots, infrastructure-as-code snippets, and sample log records.

Step 5: Prove it operates (review + follow-up)

AU-2 is about event identification and coordination, but auditors will still test whether logs are “real” in operations. Keep:

• Review records (daily/weekly SOC checks, alert triage)
• Tickets and escalations tied to log events
• Tuning decisions (what got suppressed and why)

This aligns with the practical expectation to “keep review evidence, follow-up tickets, and escalation records” as operating proof ¹.

Required evidence and artifacts to retain

Keep artifacts in an assessor-friendly bundle mapped to AU-2:

1. Event Log Catalog (version-controlled; shows event types, sources, owners)
2. Coordination evidence (stakeholder list, meeting notes, approvals, agency coordination record if applicable)
3. Logging architecture diagram (sources → collectors → SIEM/log archive)
4. Configuration evidence (cloud audit logging settings, SIEM connectors, agent policies, IaC)
5. Sample log exports (redacted if needed, but demonstrate key event types and required fields)
6. Operational evidence (review attestations, alert queues, investigation tickets tied to log events)
7. Change management linkages (changes to logging rules tracked and approved)

FedRAMP assessors expect documentation that fits the FedRAMP package structure, so store these where you can quickly attach them to the applicable SSP/control implementation description ².

Common exam/audit questions and hangups

Expect these, and pre-answer them in your evidence:

• “Show me the list of events you log.” If you respond with “everything,” you will be asked how you ensure completeness and quality. Provide the catalog.
• “Who decided this event set and why?” Produce the coordination record and decision log ¹.
• “Prove logs are generated from within the boundary.” Provide source list + sample events from boundary systems.
• “How do you know logging didn’t break after a deployment?” Show monitoring/health checks for log pipelines and change tickets tied to logging components.
• “Can an admin disable logging without detection?” Be ready to explain access controls and alerting on logging configuration changes (even if that maps to other AU controls, it supports credibility).

Frequent implementation mistakes (and how to avoid them)

1. Mistake: Treating AU-2 as a SIEM checkbox.
   Fix: Make the Event Log Catalog a governed artifact owned by security/GRC with engineering input, updated through change control.

2. Mistake: No coordination trail.
   Fix: Keep a lightweight decision record: attendees, event categories agreed, open gaps, next steps ¹.

3. Mistake: Logging sources exist, but event types are unclear.
   Fix: Document event types explicitly (admin actions, auth events, data access signals) and show examples in exported logs.

4. Mistake: Critical SaaS/control-plane logs ignored.
   Fix: Include identity, CI/CD, and cloud control plane auditing in the catalog. Assessors often probe these because they show who changed what.

5. Mistake: Evidence is scattered.
   Fix: Centralize artifacts and map them to AU-2. Tools like Daydream reduce the “evidence scavenger hunt” by linking control statements to the exact config snapshots and tickets.

Risk implications (why operators get burned)

If you cannot show what you log and why, you create two failure modes:

• Detection gap: Suspicious activity can blend into normal operations if key events are not captured or cannot be correlated ¹.
• Assurance gap: During authorization and continuous monitoring, you may not be able to demonstrate control operation. That delays ATO decisions and creates repeat findings that consume engineering capacity.

A practical 30/60/90-day execution plan

Use these phases as a project skeleton. Adjust scope to your boundary size.

First 30 days (baseline and decisions)

• Produce the first version of the Event Log Catalog covering all in-boundary components.
• Identify log consumers and run the coordination session; capture decisions and approvals ¹.
• Document current log routing architecture and gaps (missing sources, broken collectors, insufficient fields).

Days 31–60 (instrumentation and validation)

• Implement missing log sources and event types from the catalog backlog.
• Validate end-to-end ingestion with test events for each critical source.
• Establish log pipeline health monitoring and an on-call path for ingestion failures.
• Start retaining operating evidence: review records and incident tickets linked to logs.

Days 61–90 (operationalization and assessor readiness)

• Run an internal “mini-assessment”: pick sample events and trace from source → SIEM → ticket.
• Tighten role-based access to logging configuration and log data.
• Package AU-2 evidence in the format you will hand to a 3PAO, aligned to FedRAMP documentation expectations ².
• Put the catalog under formal change control so it stays current.

Frequently Asked Questions

Do we have to log every possible event the system can generate to meet AU-2?

AU-2 requires you to identify the event types the system is capable of logging and select events that support audit needs, with documented coordination on those needs ¹. Your goal is a defensible event set with clear rationale and ownership, not maximum volume.

What counts as “coordination with other organizational entities”?

Written evidence that you aligned event logging requirements with teams that consume audit data, such as SOC, incident response, IAM, and the customer agency security team where applicable ¹. Meeting notes plus a decision record tied to the event catalog is usually enough.

How do we operationalize AU-2 if key infrastructure is run by a third party?

Keep AU-2 ownership internal, then require the third party to provide the event types and access you need through contract language, technical integration, and periodic verification. Your Event Log Catalog should still list the source, the third party interface, and how you validate delivery.

What evidence do assessors typically accept for AU-2?

A current event log catalog, proof that logging is enabled across the boundary, sample log entries that demonstrate required event types, and records showing logs are reviewed and lead to follow-up actions ¹. Packaging evidence in FedRAMP-friendly formats reduces churn ².

We have lots of application logs. Do those satisfy AU-2?

Application logs help only if they capture audit-relevant event types (auth, admin actions, data access signals) with consistent fields and reliable forwarding to your central log store. Document them in the catalog and show sample entries that support investigations.

How should we keep the Event Log Catalog current as systems change?

Put the catalog under change control and tie updates to your SDLC and infrastructure change workflow. If you use Daydream, link catalog entries to change tickets and evidence attachments so updates become part of normal release work rather than a quarterly scramble.

Footnotes

1. NIST Special Publication 800-53 Revision 5

2. FedRAMP documents and templates