AU-13(3): Unauthorized Replication of Information

AU-13(3) requires you to run discovery techniques, processes, and tools that can detect whether external entities (third parties, unknown parties, or compromised accounts outside your boundaries) are replicating your organization’s information without authorization. To operationalize it fast, define what “replication” means for your data, instrument monitoring across likely exfiltration/clone paths, and prove a repeatable review-and-response cadence with retained evidence. ¹

Key takeaways:

• AU-13(3) is a detection requirement focused on external unauthorized copying, not just internal access control. ¹
• Auditors will look for a runbook, ownership, tool coverage, and evidence of recurring execution and follow-up. ¹
• “Discovery” should cover internet exposure, third-party sharing paths, and signals of bulk transfer or dataset duplication.

AU-13(3): Unauthorized Replication of Information is easy to misunderstand because it sits near logging and monitoring concepts, but it targets a specific failure mode: your information gets copied outside your control and you don’t detect it. “External entities” includes legitimate third parties acting outside contract terms, unknown parties scraping or reposting data, compromised partner accounts, or someone mirroring a dataset to infrastructure you don’t manage.

Operationally, this requirement forces a concrete answer to three questions: (1) what information would matter if replicated, (2) where replication is most likely to occur, and (3) what signals and review actions prove you would catch it in time to contain and remediate. The fastest path is to treat AU-13(3) like a control with a run cadence: define scope, deploy discovery methods, review alerts on a schedule, investigate exceptions, and retain evidence.

If you already run DLP, CASB/SSE, cloud audit logging, egress monitoring, and threat intel/domain monitoring, AU-13(3) is often an integration and governance exercise. If you do not, AU-13(3) becomes the forcing function to pick a minimum viable monitoring stack and document the operating procedure.

Regulatory text

Requirement (AU-13(3)): “Employ discovery techniques, processes, and tools to determine if external entities are replicating organizational information in an unauthorized manner.” ¹

What the operator must do

You must (a) implement discovery coverage that can surface unauthorized copying of organizational information by external entities, (b) run it as an operational process rather than a one-time setup, and (c) be able to demonstrate it works through evidence (alerts, reviews, investigations, and outcomes). The text is intentionally flexible about tooling, but not flexible about the outcome: you need a reasonable way to detect unauthorized replication outside your boundary. ¹

Plain-English interpretation

AU-13(3) means: don’t rely on hope or contract terms to prevent copying. Put monitoring and discovery in place to detect when your data is being duplicated externally, then investigate and respond.

“Replication” should be interpreted broadly in a way that matches your environment:

• Bulk exports (manual or automated) from SaaS platforms
• Mirroring cloud storage buckets/containers to external accounts
• Large downloads via managed file transfer, SFTP, or collaboration links
• Copying source code or model weights to external repos
• Data reposted on public sites, paste sites, code forges, or cloud shares

Who it applies to (entity and operational context)

AU-13(3) is most relevant for:

• Federal information systems and programs adopting NIST SP 800-53 controls. ²
• Contractor systems handling federal data, including environments where third parties, subcontractors, or SaaS services touch controlled information. ¹

Operational contexts where auditors expect stronger AU-13(3) execution:

• High-volume data platforms (data lakes, analytics, HR/finance systems)
• Collaboration-heavy environments (M365/Google, Slack/Teams, ticketing)
• Third-party data sharing (ETL partners, claims processors, MSPs)
• Cloud-native stacks with frequent role changes and external identities

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

1) Write a one-page “control card” operators can run

Create a requirement-level runbook that answers, plainly:

• Objective: detect unauthorized external replication of organizational information. ¹
• Owner: Security Operations or GRC with named technical delegate.
• Scope: systems, datasets, and third-party channels in scope.
• Cadence: how reviews happen (event-driven + scheduled review).
• Triggers: suspected exfiltration, third-party offboarding, new sharing integrations, major incidents.
• Exceptions: approved replication paths (e.g., contracted processors) with approvals and logging requirements.

In Daydream, teams commonly operationalize this as a “requirement control card” with owners, triggers, steps, and exception rules so audits don’t stall on tribal knowledge.

2) Define what “unauthorized replication” means in your environment

Create a short standard that can be tested:

• Unauthorized destinations: personal email, personal cloud drives, unapproved external tenants/accounts, unknown IP ranges, unmanaged devices, public repos.
• Unauthorized methods: bulk export, API extraction outside approved apps, scraping, mass download via sharing links.
• Unauthorized purpose: activity outside contract/SOW, outside DPA terms, or outside internal approvals.

Tie the definition to your data classification scheme so response urgency is consistent.

3) Map your highest-risk replication paths

Build a simple matrix and keep it current:

Replication path	Likely external entity	Discovery signals	Primary tools/log sources
SaaS exports (CRM/HR/ITSM)	Third party user, compromised account	Unusual export volume; new API token; after-hours export	SaaS audit logs, IAM logs, SIEM
Cloud storage copy	External cloud account	Cross-account copy; public ACL; new sharing principal	Cloud audit logs, CSPM
Email forwarding	External mailbox	Auto-forward rules; mass attachments	Email security, M365/Google logs
Collaboration links	Anonymous/public users	Public link creation; spikes in downloads	DLP/CASB/SSE, platform logs
Code/data repos	Public internet	Repo visibility changes; cloning spikes	SCM audit logs, egress monitoring

Auditors don’t require this exact table, but they will expect you to show you identified where replication could happen.

4) Implement “discovery techniques, processes, and tools”

Pick coverage that matches your reality. A practical minimum set looks like:

Inside your boundary (signals of outbound copying):

• Centralize audit logs for cloud, SaaS, IAM, email, file sharing, and endpoints.
• Alert on bulk export indicators (volume anomalies, mass downloads, unusual geo/IP, new OAuth apps/tokens).
• Monitor network egress patterns that indicate large transfers to external destinations.

At the boundary (controls that also produce discovery evidence):

• DLP policies for regulated data types and sensitive tags.
• CASB/SSE policies for uploading to unsanctioned apps.
• Conditional access and session controls that block or step-up auth for high-risk downloads.

Outside your boundary (evidence of public replication):

• Internet exposure monitoring for leaked files, public buckets, or shared links indexed externally.
• Domain/repo monitoring for your organization name, sensitive project names, or known data markers.

AU-13(3) does not mandate specific products; it mandates that your combination of methods can reasonably detect external replication. ¹

5) Run a repeatable review-and-response cycle

Document the operating rhythm:

• Triage alerts daily (or per your SOC model).
• Hold a recurring “AU-13(3) review” where you review: top alerts, false positives, tuning changes, open investigations, and third-party issues.
• For confirmed events: contain, preserve evidence, notify stakeholders (legal/privacy/customer as applicable), and open corrective actions.

Track every confirmed or suspected replication event to closure with lessons learned. If you use Daydream, treat these as remediation items tied to the AU-13(3) requirement so you can show validated closure and due dates during audits.

6) Manage third-party pathways explicitly

Because AU-13(3) calls out external entities, align third-party governance to the monitoring:

• Contractually require logging, breach/incident notice, and cooperation for investigations.
• Maintain an inventory of approved data replication flows to third parties (purpose, dataset, method, endpoints).
• Offboarding: disable external accounts, rotate tokens, revoke shares, and confirm data return/deletion where required.

7) Prove it works with control health checks

Schedule periodic control health checks:

• Confirm critical log sources are connected and not degraded.
• Sample recent alerts and confirm investigations occurred.
• Validate tuning changes were approved and documented.

This closes the most common audit gap: teams have tools, but cannot show consistent operation. ¹

Required evidence and artifacts to retain

Retain evidence that shows both design and operation:

Design artifacts

• AU-13(3) control card/runbook (owner, scope, cadence, triggers, exceptions)
• Data classification and “unauthorized replication” definition
• Monitoring coverage map (systems + log sources + alert catalog)
• Third-party approved sharing/replication register

Operating evidence

• Screenshots/exports showing key log sources enabled (cloud/SaaS audit logging settings)
• SIEM/DLP/CASB alert rules or detections (names, conditions, severity, routing)
• Samples of alert tickets with triage notes and outcomes
• Investigation reports for confirmed/suspected incidents
• Tuning change records (what changed, who approved, why)
• Control health check results and remediation tracking to closure

Keep evidence in a single repository with a predictable naming convention so you can answer exams quickly.

Common exam/audit questions and hangups

Expect these lines of questioning:

• “Define ‘replication’ and show how you detect it for your highest-risk datasets.”
• “Which external entities are in scope: vendors, partners, customers, contractors?”
• “Show the last review cycle: who reviewed, what they looked at, what actions resulted.”
• “How do you distinguish authorized third-party processing from unauthorized copying?”
• “What happens if logs are missing for a critical SaaS platform?”
• “Show one investigation end-to-end, including containment and corrective actions.”

Hangup that derails audits: the team points to DLP policy documents but cannot show recurring review evidence or investigations tied to specific detections.

Frequent implementation mistakes and how to avoid them

1. Treating AU-13(3) as a policy-only control
   Fix: require operating evidence (alerts, reviews, tickets) as part of the control definition.

2. Monitoring only internal access, not external replication paths
   Fix: include sharing links, exports, third-party access, and cross-tenant/cloud transfers in your detection catalog.

3. No exception register for “authorized replication”
   Fix: maintain an approved replication register so investigators can quickly classify events.

4. Tool sprawl with unclear ownership
   Fix: name an AU-13(3) operator and define handoffs between SecOps, IAM, IT, and third-party risk.

5. No feedback loop
   Fix: every confirmed/suspected event must result in tuning or control changes, and you should retain that record.

Enforcement context and risk implications

No public enforcement cases were provided in the source catalog for this requirement, so this page does not cite specific actions.

Risk-wise, AU-13(3) maps to a common failure pattern in incidents and contract disputes: copied data appears outside your environment and you cannot establish when it happened, what was taken, and whether it was authorized. That creates downstream exposure across breach notification, customer commitments, and federal contract performance expectations. ²

A practical 30/60/90-day execution plan

First 30 days (stabilize scope and minimum detection)

• Assign control owner and publish the AU-13(3) control card.
• Define “replication” and “unauthorized” with Security, Legal/Privacy, and data owners.
• Inventory top systems and third-party sharing channels.
• Turn on/verify audit logging for the highest-risk SaaS and cloud services.
• Stand up initial alerts: bulk export, mass download, public link creation, new OAuth app/token with high-privilege scopes.

Days 31–60 (operationalize reviews and third-party pathways)

• Launch recurring review meetings and ticketing workflow for investigations.
• Build the authorized replication register for third parties and internal teams.
• Implement or tune DLP/CASB/SSE controls for the most sensitive data types.
• Run a tabletop exercise: “third party replicates data outside contract terms” and test your evidence capture.

Days 61–90 (prove sustained operation and improve coverage)

• Perform the first control health check and document results.
• Expand discovery to additional data stores and collaboration platforms.
• Add external monitoring appropriate to your exposure (public repos, shared links, misconfigured storage).
• Close the loop: track remediation items to validated closure and retain the evidence bundle.

Daydream fits naturally in this phase as the system of record for the AU-13(3) control card, the minimum evidence bundle, and recurring control health checks, so you can answer audits without rebuilding context each cycle.

Frequently Asked Questions

Does AU-13(3) require a specific tool like DLP or a CASB?

No. The requirement is outcome-based: you must employ discovery techniques, processes, and tools that can determine whether external entities are replicating information without authorization. ¹

What counts as an “external entity” for AU-13(3)?

Treat any party outside your organizational boundary as external: third parties (vendors, partners, subcontractors), external users/tenants, and unknown actors on the internet. The key is whether they are replicating your information without authorization. ¹

How do we separate “authorized replication” from normal third-party processing?

Maintain an approved replication register that documents purpose, datasets, methods, endpoints, and approvals. Investigations should check events against that register before escalating.

What evidence will an auditor accept to show the control is operating?

Provide a runbook/control card, detection rules, recent alert samples with tickets, investigation notes, review meeting records, and health check results. Tie evidence to a consistent cadence so it’s clear the control runs repeatedly.

We outsource SOC monitoring. Who owns AU-13(3)?

Your organization still owns the requirement. Assign an internal control owner responsible for ensuring the third party monitors the right signals, escalates appropriately, and provides evidence you can retain.

How do we handle false positives without weakening the control?

Tune rules with documented rationale and approvals, and keep a record of before/after behavior. Auditors generally accept tuning when you can show you reviewed alerts, improved signal quality, and preserved detection for high-risk replication paths.

Footnotes

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

2. NIST SP 800-53 Rev. 5