AU-13: Monitoring for Information Disclosure

To meet the au-13: monitoring for information disclosure requirement, you must continuously monitor defined systems and audit records for evidence that organizational information was disclosed without authorization, then respond through triage, containment, and documented follow-up. Operationalize AU-13 by scoping what you monitor, deploying detections, assigning ownership, and retaining repeatable evidence of monitoring and response.

Key takeaways:

• AU-13 is a detection-and-evidence control: show what you monitor, how you detect disclosure, and how you handle alerts.
• Scope decisions drive everything: define data types, systems, audit sources, and disclosure indicators before tuning tools.
• Audit readiness depends on artifacts: procedures, detection logic, alert tickets, and recurring review records.

AU-13 sits in the Audit and Accountability family, but auditors will treat it as a practical “can you detect data leakage” control, not a paperwork exercise. The requirement expects you to monitor defined inputs (systems, components, and audit sources you specify) for evidence that organizational information was disclosed without authorization. In practice, this means your logging pipeline, SIEM, DLP, CASB/SSE, email security, endpoint telemetry, and cloud control-plane logs must work together to detect indicators of disclosure and route them into an incident workflow you can prove you run.

For a CCO, GRC lead, or Compliance Officer, the fastest path is to convert AU-13 into an operating requirement with three decisions: (1) what “organizational information” means for your environment (data classifications and regulated data types), (2) where disclosure would show up (authoritative log sources and data egress channels), and (3) what “evidence of unauthorized disclosure” looks like (alert logic, thresholds, and investigation steps). Once those are pinned down, you can assign a control owner, implement detections, and build an evidence kit that survives an assessment.

Regulatory text

Requirement (excerpt): “Monitor {{ insert: param, au-13_odp.01 }} {{ insert: param, au-13_odp.02 }} for evidence of unauthorized disclosure of organizational information; and” ¹

How to read this operationally: AU-13 requires you to (a) define the monitoring scope (the placeholders represent organization-defined parameters such as the systems, components, audit records, and/or monitoring tools you select), and (b) perform monitoring for indicators that data left authorized boundaries. Your assessor will expect specificity: named log sources, named data egress paths, detection content, and a repeatable process for alert handling ².

Plain-English interpretation (what AU-13 is really asking)

You need a working capability to detect suspected data disclosure and prove you are watching the right places. “Unauthorized disclosure” includes obvious events (publicly accessible storage, misrouted email, exfiltration malware) and subtle ones (over-permissive sharing links, copied data to unmanaged devices, third-party integrations exporting records).

AU-13 is not satisfied by “we have a SIEM” or “we have DLP turned on.” It is satisfied when you can show:

1. a documented scope of what is monitored,
2. detection logic tied to disclosure risks, and
3. evidence of ongoing operation (alerts, triage, and follow-up).

Who it applies to (entity and operational context)

AU-13 is most directly applicable to:

• Federal information systems and programs adopting NIST SP 800-53 controls ².
• Contractor systems handling federal data, including cloud and SaaS environments where disclosure could occur via misconfiguration or improper sharing ¹.

Operationally, AU-13 applies anywhere your organization stores, processes, or transmits sensitive information, including:

• Identity systems (IdP logs show unusual access tied to disclosure).
• Collaboration platforms (file shares, external invites, public links).
• Cloud storage and databases (policy changes, public exposure, unusual downloads).
• Endpoints (mass copy to removable media; suspicious compression tools).
• Email and messaging (bulk forwarding; outbound attachments with sensitive content).
• Third-party connections (API exports, data sync apps, managed services).

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

Step 1: Set AU-13 scope in writing (your “organization-defined parameters”)

Create an AU-13 monitoring scope statement that names:

• Data in scope: your data classification levels plus any regulated data types you track internally.
• Systems in scope: production systems, critical SaaS, and admin/control planes where sharing and export occur.
• Monitoring sources: which audit records/logs and which tools generate AU-13 alerts.
• Egress channels: web uploads, email, file sharing, APIs, removable media, printing (if relevant), and third-party transfers.

Deliverable: AU-13 Control Implementation Statement with scope and exclusions, with a justification for any exclusions.

Step 2: Inventory the minimum viable log sources for disclosure detection

Build a one-page mapping from “disclosure pathway” to “authoritative telemetry.” Examples:

• Public cloud storage exposure → cloud control-plane logs and config change events.
• Large data exports from SaaS → SaaS audit logs for export actions and admin changes.
• Unusual outbound traffic → network egress logs, proxy logs, DNS logs (if in use).
• Sensitive content leaving endpoints → endpoint DLP/EDR telemetry.

Make each log source accountable: owner, retention location, and health monitoring (missing logs are a common audit finding).

Step 3: Define “evidence of unauthorized disclosure” as alertable indicators

Write a short AU-13 detection standard with categories such as:

• Misconfiguration exposure: public access enabled, anonymous links created, sharing to unauthorized domains.
• Suspicious access patterns: impossible travel tied to downloads; atypical bulk reads.
• Exfiltration signals: large outbound transfers, unusual upload destinations, data staging behavior.
• Policy violations: transfers to unapproved third parties; use of personal email; unmanaged device access.

Tie each category to at least one detection rule, query, or product policy you can show in an assessment.

Step 4: Implement detections and route them to a single response workflow

Operational minimum:

• Centralize alerts in a ticketing or incident platform.
• Create an AU-13 triage runbook: validate alert, confirm data type, identify recipient/destination, assess authorization, contain, notify stakeholders, and document outcome.
• Define escalation paths (Security Operations, Privacy, Legal, business owner) based on your internal thresholds.

One common operational decision: treat AU-13 alerts as “security incidents” only after triage, but still require a ticket and closure notes for every AU-13 signal.

Step 5: Prove monitoring is continuous with recurring reviews

Assessors will ask “how do you know it’s working?” Set recurring operational checks:

• Alert volume review (is it zero because it’s broken?).
• Log source health review (are connectors failing?).
• Detection tuning review (false positives, coverage gaps).
• Sampling review (pick closed AU-13 tickets and confirm runbook steps were followed).

If you use Daydream for control management, map AU-13 to a named control owner, link the runbook and detection inventory, and schedule recurring evidence requests so you can produce an audit-ready package on demand.

Required evidence and artifacts to retain

Keep artifacts that prove design and operation:

Design evidence

• AU-13 control narrative (scope, monitored systems, definitions of disclosure indicators).
• Monitoring architecture diagram (high level is fine; show data sources → SIEM/DLP → ticketing).
• Detection catalog (rule names, descriptions, mapped log sources).
• AU-13 triage runbook and escalation matrix.

Operating evidence

• Sample AU-13 alerts/tickets with timestamps, triage notes, and closure rationale.
• Screenshots or exports showing detection rules enabled and last triggered times.
• Log source health reports (connector status, ingestion errors, gaps).
• Recurring review meeting notes or attestations (who reviewed, what changed).

Retention length is program-specific; keep evidence long enough to cover your assessment period and any contractual requirements tied to the systems in scope.

Common exam/audit questions and hangups

Expect these questions:

• “What exactly are you monitoring for AU-13, and where is that documented?” (scope clarity)
• “Show me the audit records that support these detections.” (log source traceability)
• “How do you determine whether disclosure was unauthorized?” (authorization logic)
• “Show closed tickets that demonstrate triage and containment.” (operating effectiveness)
• “How do you ensure monitoring didn’t silently fail?” (health checks and reviews)

Hangups that stall audits:

• No explicit definition of “organizational information” in scope.
• Detections exist but are not mapped to specific data egress paths.
• Alerts route to email inboxes with no ticketing and no closure evidence.

Frequent implementation mistakes (and how to avoid them)

1. Mistake: Treating AU-13 as a pure SIEM control.
   Fix: Include DLP/CASB/SaaS audit logging and cloud control-plane monitoring where disclosure happens.

2. Mistake: No “unauthorized” decision rule.
   Fix: Document how authorization is evaluated (approved third parties, approved sharing domains, approved integrations, business owner approval).

3. Mistake: Over-scoping without telemetry.
   Fix: Scope to systems where you can collect reliable audit records now, then expand deliberately with an intake plan.

4. Mistake: Evidence is ad hoc.
   Fix: Standardize artifacts (control narrative, detection catalog, ticket samples, recurring review record) and collect them on a schedule.

Enforcement context and risk implications

No public enforcement cases were provided in the source catalog for this requirement, so you should treat AU-13 primarily as an assessment-readiness and breach-prevention control rather than anchoring it to a specific penalty narrative. The risk is straightforward: if you cannot detect disclosure quickly, you will struggle to contain it, investigate it, and support downstream legal/privacy obligations. AU-13 also tends to expose broader program weaknesses: incomplete logging, unclear data classification, and weak third-party data sharing governance.

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

Use phases so you can start operating quickly and expand coverage without stalling.

First 30 days (stand up audit-ready minimum)

• Assign a single AU-13 control owner and backups.
• Write the AU-13 control narrative with a tight scope statement.
• Identify top disclosure channels (cloud storage, collaboration, email, API exports) and select authoritative log sources for each.
• Stand up an AU-13 ticket workflow and triage runbook.
• Enable a starter set of detections and confirm alerts generate tickets.

By 60 days (improve coverage and reduce blind spots)

• Expand log source onboarding for any high-risk systems missing telemetry.
• Build a detection catalog with rule owners and tuning notes.
• Add recurring reviews: alert volume, ingestion health, sampling closed tickets.
• Document authorization logic for common sharing patterns, including third-party integrations and managed service providers.

By 90 days (operate like a program, not a project)

• Run a tabletop exercise using an AU-13 scenario (misconfiguration exposure or bulk export) and capture lessons learned.
• Tune detections based on ticket outcomes and false positives.
• Produce a packaged evidence kit (design + operating evidence) that you can hand to an assessor with minimal effort.
• If you use Daydream, automate recurring evidence collection and map artifacts directly to AU-13 so audit prep becomes a pull, not a scramble.

Frequently Asked Questions

What counts as “organizational information” for AU-13?

Define it in your scope statement using your internal data classification policy and the systems that store or process that data. Auditors want a clear boundary: what data types are monitored and where disclosure would be detected.

Do I need DLP to satisfy AU-13?

AU-13 requires monitoring for evidence of unauthorized disclosure, not a specific product. Many programs meet it using a mix of SIEM detections, SaaS audit logs, cloud configuration monitoring, and endpoint/network signals, backed by tickets and a runbook.

How do I prove the monitoring is working?

Keep operating evidence: generated alerts, tickets with triage notes, and recurring log-ingestion health checks. Also retain proof that detections are enabled (exports or screenshots) and that someone reviews outcomes.

How do third parties fit into AU-13?

Treat third-party data transfers as a primary disclosure pathway. Monitor for unapproved sharing destinations, new integrations, abnormal exports, and access from third-party accounts, and document your “authorized vs unauthorized” decision rule.

What if my SIEM has too many false positives?

Start with a narrow set of high-signal detections tied to concrete disclosure paths (public links, bulk exports, policy changes). Track tuning changes in the detection catalog and show that you review alert quality as part of operations.

What artifact do auditors ask for most often?

A tight AU-13 control narrative plus a few representative tickets that show end-to-end handling. Pair those with a detection catalog that ties each rule to a log source and a disclosure indicator.

Footnotes

1. NIST SP 800-53 Rev. 5 OSCAL JSON

2. NIST SP 800-53 Rev. 5