Safeguard 3.2: Establish and Maintain a Data Inventory

Safeguard 3.2 sits in the CIS Controls v8 data protection family and asks a deceptively simple question: “Do you actually know what data you have and where it lives?” If your answer depends on tribal knowledge, spreadsheets with unknown owners, or a one-time discovery exercise, you will struggle to defend your security program in audits, customer diligence, and incident response. A usable data inventory is not a documentation project. It is an operational control that connects systems, people, and processes: product teams create data, IT and Security store and protect it, Legal and Privacy constrain its use, and Procurement/TPRM governs where it flows outside your environment.

This page is written for a Compliance Officer, CCO, or GRC lead who needs to implement safeguard 3.2 quickly, with minimal ambiguity. It focuses on practical design decisions (scope, data objects, owners, tooling), execution steps (how to build and keep it current), and the evidence bundle auditors typically expect to see. Source references are limited to CIS Controls v8 and CIS Controls Navigator v8, per your provided catalog (CIS Controls v8; CIS Controls Navigator v8).

Regulatory text

Framework requirement (excerpt/summary): “CIS Controls v8 safeguard 3.2 implementation expectation (Establish and Maintain a Data Inventory).” (CIS Controls v8; CIS Controls Navigator v8)

Operator interpretation: You must (1) establish a documented inventory of organizational data and (2) maintain it over time. “Maintain” is the operative word. Auditors and customers will test whether the inventory is complete for your defined scope, whether it has clear ownership, and whether updates happen through an intentional mechanism rather than ad hoc edits (CIS Controls v8; CIS Controls Navigator v8).

What this means in practice:

• The inventory must identify key data sets (not just systems), where they are stored/processed, and who is accountable for accuracy.
• The inventory must capture data movement (ingress, internal transfers, egress to third parties) at a level that supports security controls.
• The inventory must be kept current through trigger events (new systems, new integrations, new third parties, material product changes) and recurring review (CIS Controls v8).

Plain-English interpretation (what you’re being asked to prove)

You need to be able to answer, quickly and consistently:

1. What data do we have? (customer data, employee data, IP, logs, telemetry, financial, etc.)
2. Where is it? (apps, databases, file stores, SaaS, endpoints, backups, data warehouses)
3. Who owns it? (business/data owner + technical owner/custodian)
4. How does it move? (sources, destinations, interfaces, third parties)
5. How is it protected? (classification, access model, encryption, retention, monitoring)
6. How do we keep this accurate over time? (workflows and evidence)

If any of those answers are “we think” or “ask Bob,” your safeguard 3.2 implementation will not hold up under scrutiny.

Who it applies to

Entity types: Enterprises, service organizations, and technology organizations adopting CIS Controls v8 as a baseline or as a customer/contract requirement (CIS Controls v8; CIS Controls Navigator v8).

Operational contexts where this becomes mandatory fast:

• You host or process customer data (especially multi-tenant SaaS).
• You use multiple SaaS platforms and data stores across teams.
• You share data with third parties (processors, sub-processors, analytics, support tooling, marketing platforms).
• You have undergone M&A, major system migrations, or rapid product changes.
• You need faster incident response (knowing what data was in a compromised system is often the hardest part).

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

Step 1: Define scope and the “data object” model

Start by writing down what “counts” as inventoried data in your organization:

• Data domains: customer, employee/HR, finance, security telemetry, product analytics, source code/IP, regulated data types (if applicable to your business).
• Data objects (recommended): define inventory records as data sets (e.g., “Customer Billing Records,” “Support Ticket Attachments,” “Authentication Logs”), not just systems. Systems change; data sets persist.

Decision point: If you cannot identify data sets yet, begin with systems as a temporary proxy, then mature into data sets once discovery and ownership stabilize.

Step 2: Assign owners and RACI

For every inventory record, assign:

• Data Owner (business): accountable for appropriate use, sharing approval, and classification.
• Data Custodian (technical): accountable for storage, access control implementation, encryption, backups, and deletion mechanics.
• GRC owner: accountable for the control operation, evidence, and reporting.

One common failure mode is “Security owns the spreadsheet.” That breaks as soon as Engineering changes architecture.

Step 3: Choose a system of record and minimum fields

Pick one authoritative place where the inventory lives (GRC tool, CMDB with extensions, data catalog, or a controlled repository). Then standardize fields. Minimum recommended fields:

Field	Why it matters in audits and operations
Data set name + description	Prevents duplicate/ambiguous records
Business owner + tech custodian	Proves accountability and maintenance
Systems/locations	Establishes where data resides
Data classification	Drives control requirements
Sensitive elements present (free text or tags)	Supports DPIA/PIA, incident response scoping
Inbound sources + outbound destinations	Documents data flows and third-party transfers
Third parties receiving/processing	Connects to TPRM and contract controls
Retention requirement + deletion method	Supports lifecycle control testing
Access model (roles/groups)	Ties to IAM and least privilege
Protection notes (encryption, tokenization, masking)	Links inventory to safeguards
Last review date + next review trigger	Proves maintenance

Step 4: Populate the baseline inventory (fast, then refine)

Build your first pass using high-signal sources:

• Architecture diagrams and service maps
• Cloud account inventories (storage, databases, data warehouses)
• SaaS app list (SSO catalog, procurement records)
• Existing data maps from Privacy/Legal (if any)
• Third-party list from Procurement/TPRM (where data is shared)

Then validate with a structured working session per domain (Finance, Product, HR, Security). Keep sessions short and evidence-driven: “show me the system and the data flow,” not “talk me through it.”

Step 5: Integrate maintenance triggers into change workflows

“Maintain” means the inventory updates as the environment changes. Implement triggers that create an inventory update task:

• New system introduced (IT intake, cloud account creation, new SaaS procurement)
• New integration/API that moves data between systems
• New third party that receives data, or a material scope change with an existing third party
• Material product change that introduces new data collection or storage
• Data store migration (e.g., new warehouse, new backup solution)

Practical implementation: add a mandatory “Data inventory impact” question to (a) procurement intake, (b) architecture review, and (c) change management. Require the data owner to attest that the inventory record was created/updated.

Step 6: Run recurring control health checks

Do not treat this as set-and-forget. Run a lightweight health check that answers:

• Are there systems with production data not linked to any inventory record?
• Are there inventory records without owners?
• Are third-party recipients documented for high-risk data sets?
• Are “last reviewed” fields stale?

Track findings through remediation tickets to validated closure with due dates, and keep evidence of closure (CIS Controls v8).

Step 7: Define exceptions and compensating controls

You will have gaps: legacy apps, shadow IT, acquired systems, or constrained teams. Define exception rules:

• What qualifies for an exception
• Who can approve it (usually Security + data owner)
• Time bound and remediation plan
• Compensating controls (restricted access, additional monitoring, or data minimization)

This protects you during audits because you can show governance, not denial.

Required evidence and artifacts to retain

Treat evidence as a package you can hand to an auditor or customer quickly.

Core artifacts

• Data inventory export/snapshot (date-stamped) from the system of record
• Data inventory standard / procedure (how records are created, updated, reviewed)
• RACI or ownership mapping (data owner, custodian, GRC)
• Change triggers documentation (procurement intake form fields, architecture review checklist, change ticket template)

Operational evidence ¹

• List of inventory updates with approver (who confirmed accuracy)
• Discovery outputs or system lists used to reconcile completeness (cloud resource lists, SaaS list)
• Control health check report and remediation tracker
• Exception register with approvals and closure evidence

Retention guidance (practical)

• Keep prior snapshots and review outputs so you can show historical operation, not just the current state.

Common exam/audit questions and hangups

Auditors tend to probe the same weak points:

1. “How do you know it’s complete?”
   Expect to show reconciliation between discovery sources (cloud/SaaS lists) and the inventory.

2. “Who owns each entry, and how do they attest?”
   If ownership is missing or informal, the control fails operationally.

3. “Show me how changes get captured.”
   They will sample new systems, recent integrations, or a new third party and ask where the inventory was updated.

4. “How does the inventory drive controls?”
   Be ready to point to downstream linkages: access reviews, encryption requirements, retention schedules, and third-party risk reviews.

Frequent implementation mistakes (and how to avoid them)

• Mistake: Inventory of systems only, no data sets.
  Fix: start with systems if needed, but add a roadmap to mature into data sets for critical domains first (customer data, HR, finance).

• Mistake: No maintenance mechanism.
  Fix: hard-wire triggers into procurement, architecture review, and change management tickets.

• Mistake: Inventory lives in a spreadsheet with unclear access control and change history.
  Fix: move to a system of record with role-based editing, change history, and exportable snapshots.

• Mistake: Ownership assigned to Security only.
  Fix: make business units own the “what/why,” and technical teams own the “where/how.”

• Mistake: No tie-in to third parties.
  Fix: add explicit fields for third-party recipients and link to your TPRM inventory. If a third party receives the data, the contract and risk review should reference the same data set names.

Enforcement context and risk implications

No public enforcement cases were provided in your source catalog for this specific safeguard, so this page does not cite enforcement outcomes.

Operational risk is still clear:

• Without a data inventory, you will struggle to scope incidents, fulfill data deletion requests, answer customer security questionnaires, or prove that third parties only receive approved data.
• The most common audit failure is not “you missed one database.” It is “you cannot demonstrate governance over changes, ownership, and evidence of ongoing maintenance.”

Practical 30/60/90-day execution plan

First 30 days: Stand up the control and baseline inventory

• Appoint a control owner in GRC and name data owners for major domains.
• Define the minimum required fields and choose the system of record.
• Produce a baseline inventory from available sources (cloud, SaaS, known databases).
• Draft the runbook: how to create/update entries, approvals, exceptions, and where evidence is stored.

Days 31–60: Make it real with triggers and reconciliation

• Add “data inventory impact” steps to procurement intake and architecture/security review.
• Build a reconciliation routine: compare cloud/SaaS inventories to the data inventory and open remediation tickets for gaps.
• Run a first control health check and close the highest-risk gaps (missing owners, unknown third-party sharing).

Days 61–90: Mature coverage and prove sustainment

• Expand from systems-as-proxy to data sets for the highest-risk areas (customer and employee data first).
• Add links from inventory entries to access control artifacts, retention schedules, and third-party records.
• Produce an audit-ready evidence bundle: dated snapshots, approvals, health check outputs, exceptions, and closure tickets.

Where Daydream fits naturally: use it to publish a requirement control card (objective, owner, triggers, steps, exceptions), standardize the minimum evidence bundle per cycle, and track control health checks to validated closure so you can demonstrate sustained operation (CIS Controls v8).

Frequently Asked Questions

What is the minimum “acceptable” data inventory for safeguard 3.2?

A single system of record that lists your key data sets (or systems as an interim proxy), their owners, where the data resides, and how updates are triggered and evidenced. If you cannot show maintenance mechanics and owner accountability, the inventory will not hold up in diligence.

Do I need automated discovery tooling to comply?

No. Automated discovery helps with completeness and drift detection, but safeguard 3.2 can be met with manual processes if they are consistent, owned, and evidenced. Most teams start manual, then add automation to reduce gaps.

How do I handle SaaS applications where the vendor won’t share detailed storage architecture?

Inventory what you control: the SaaS app name, the data categories stored, the business purpose, the owner, and third parties/sub-processors if known from contractual documentation. Record the uncertainty as an exception and track follow-up through procurement/TPRM.

How detailed do data flows need to be?

Detailed enough to answer, “Where does this data go next, and who can access it?” Focus on material transfers: data warehouses, analytics pipelines, support tooling, marketing platforms, and any third party processing.

Who should approve changes to the inventory?

The data owner should attest to “what data and why,” and the custodian should confirm “where it is and how it’s protected.” GRC should validate completeness and evidence, then record the approval trail.

How do I prove the inventory is “maintained” during an audit?

Show dated snapshots/exports, a change log (or tickets) tied to trigger events, and results of recurring health checks with remediation items closed. Auditors respond well to samples that trace from a real-world change (new system or third party) to an updated inventory entry.

Footnotes

1. CIS Controls v8