Safeguard 3.3: Configure Data Access Control Lists

“Safeguard 3.3: configure data access control lists requirement” is a practical access governance requirement dressed in technical language. Your job, as a Compliance Officer, CCO, or GRC lead, is to make it auditable: define where ACLs must exist, who owns them, how changes are requested and approved, and what proof you keep.

ACLs show up in many places: file shares, SaaS workspaces, cloud storage buckets, databases, data warehouses, collaboration tools, and even application-level authorization tables. If your teams manage access through ad hoc group membership, inherited permissions, or one-off exceptions, you may still be “doing access control,” but you will struggle to show repeatable control operation.

This page gives you a requirement-level runbook: applicability, implementation steps, evidence bundles, and audit questions that map directly to how assessors test CIS Controls v8 safeguards. Where CIS is a framework (not a law), customers and auditors still expect you to implement it in a way that is testable and sustained over time. (CIS Controls v8)

Regulatory text

Framework source: “CIS Controls v8 safeguard 3.3 implementation expectation (Configure Data Access Control Lists).” (CIS Controls v8)

Operator interpretation (what you must do):

• Configure ACLs on data repositories so access is explicitly granted only to approved users, groups, roles, services, or systems.
• Ensure ACLs reflect least privilege and are maintained over time through controlled changes and periodic validation.
• Be able to prove ACL configuration and ongoing operation through records, logs, and reviews. (CIS Controls v8; CIS Controls Navigator v8)

Plain-English interpretation

You need a reliable way to answer: “Who can access this data, why, and who approved it?” for each in-scope data store. An ACL can be a traditional filesystem ACL, a cloud IAM policy attached to an object store, a database GRANT, a data warehouse role mapping, or a SaaS space permission model. The control expectation is consistent: access must be intentional, documented, and reviewable. (CIS Controls v8)

Who it applies to

Entity types: Enterprises, service organizations, and technology organizations implementing CIS Controls v8. (CIS Controls v8)

Operational contexts where 3.3 is typically in scope:

• Cloud storage and object stores (where “public” or overly broad access is a common failure mode)
• File servers and network shares
• Databases and data warehouses
• SaaS platforms holding sensitive business data (HR, finance, CRM, ticketing, collaboration)
• Third-party hosted data environments you administer (managed databases, hosted SFTP, analytics platforms)

Data types to prioritize (practical scoping):

• Regulated or sensitive data (customer data, employee data, financial data, security data)
• “High blast radius” repositories (shared drives, company-wide workspaces, central buckets)
• Data stores that back critical systems and reporting

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

1) Define the control as an executable “requirement control card”

Create a one-page control card that an auditor and an operator can both use. Minimum fields:

• Objective: ACLs restrict data access to approved identities per least privilege.
• Owner: Named role (e.g., IAM lead, platform security) and backup.
• In-scope systems: List of repositories and the system of record for that inventory.
• Trigger events: New repository, new app, new third party integration, org changes, incident findings.
• Cadence: How often you review ACLs and how often you test for drift (define internally and follow it).
• Exception rules: Break-glass access, emergency changes, inherited permissions constraints, third-party managed limitations.
• Evidence required: See “Required evidence and artifacts to retain.” (CIS Controls v8)

Practical note: This is where many teams fail. They can show technical settings, but they cannot show control design (ownership, cadence, evidence). (CIS Controls v8)

2) Build (or fix) your inventory of data repositories that require ACLs

You cannot configure or validate ACLs without knowing where data lives.

• Identify your “top repositories” first: shared file storage, cloud buckets, major SaaS, primary databases.
• Tie each repository to:
  • Business owner (data owner)
  • Technical owner (system owner)
  • Data classification (or sensitivity tier)
  • Access model (roles/groups/service accounts)
  • Logging location for access and permission changes

If you use Daydream or a GRC system, track this inventory as the control scope artifact so it stays current across audits and customer diligence.

3) Standardize ACL patterns (so teams stop inventing permissions)

Create approved patterns by repository type. Examples:

• Cloud object storage: deny-by-default, allow specific roles, block public access settings, separate read vs write roles.
• File shares: group-based permissions only, no direct user grants except documented break-glass.
• Databases: role-based grants mapped to job functions, service accounts scoped to specific schemas/tables where feasible.
• SaaS workspaces: restrict admin roles, limit “anyone can share externally,” and separate spaces/projects by sensitivity.

Deliverable: a short “ACL standard” that engineering can implement and auditors can test against. (CIS Controls v8)

4) Implement a controlled workflow for ACL changes

Treat permission changes as governed changes, not informal messages.

• Request: ticket includes repository, identity/group, access level, justification, and duration (if time-bound).
• Approval: data owner approves business need; system owner/security approves policy fit.
• Implementation: change is executed through the normal administrative path (IAM, platform tooling).
• Validation: confirm access works as intended and does not grant broader permissions.
• Logging: ensure permission change events are captured (platform audit logs) and retained per your log retention standard.

Operational shortcut that holds up in audits: “No ticket, no access.” Keep exceptions rare and documented.

5) Review and validate ACLs for drift and over-permissioning

Set two recurring activities:

• Access review: repository owners attest that ACL memberships and roles are still correct.
• Technical drift check: compare current ACL state to your standard (or baseline), and open remediation items.

Track findings to closure with owners and due dates. Auditors commonly test whether issues actually get fixed and whether closure is validated. (CIS Controls v8)

6) Prove it with a minimum evidence bundle

Decide what evidence you will always retain per review cycle and per change. Do not wait for an audit to assemble it. (CIS Controls v8)

Required evidence and artifacts to retain

Keep evidence in a consistent location with controlled access (your GRC repository, ticketing system, or evidence vault).

Evidence for control design (baseline)

• Control card (objective, scope, owner, cadence, exceptions) (CIS Controls v8)
• In-scope repository inventory with owners
• ACL standard / configuration baseline by repository type
• RACI for approvals (data owner, system owner, security)

Evidence for control operation (ongoing)

• Samples of ACL change tickets showing request, approval, implementation date, and reviewer
• System audit logs or screenshots/exported reports showing:
  • current ACLs (who has what access)
  • permission change history (where available)
• Completed access review attestations and follow-up actions
• Remediation tracker entries with validated closure (CIS Controls v8)

Practical evidence tip: for each “major” repository, keep a point-in-time export of permissions from the same date as your access review. That prevents disputes about “what the ACL was” during the review.

Common exam/audit questions and hangups

Assessors and customer auditors tend to ask:

• “Show me your in-scope data stores and how you know the list is complete.”
• “Pick one sensitive repository. Who has access today, and why?”
• “How do you prevent public or overly broad access?”
• “Show a recent access grant end-to-end: request, approval, implementation, and proof.”
• “How often do you review access, and what happens when you find issues?” (CIS Controls v8)

Hangups that slow audits:

• No clear data owner who can approve access.
• Permissions managed directly on users rather than groups/roles, which makes review unscalable.
• Review meetings happen, but no recorded outcomes or remediation trail.

Frequent implementation mistakes and how to avoid them

1. Scoping only “files,” ignoring SaaS and cloud data

• Fix: define “data repositories” broadly and maintain an inventory tied to ownership.

2. Relying on IAM alone without repository-level permissions

• Fix: confirm the effective permissions at the data layer (bucket policy, database grants, workspace permissions).

3. One-time hardening with no ongoing review

• Fix: add a recurring access review plus drift checks; retain evidence every cycle. (CIS Controls v8)

4. Exceptions become the rule (shared accounts, permanent elevated access)

• Fix: require documented justification, time bounds where feasible, and post-exception review.

5. Evidence is screenshots with no context

• Fix: pair technical exports with a short attestation: what was reviewed, who reviewed, and what changed.

Enforcement context and risk implications

CIS Controls v8 is a framework, so this requirement is usually enforced through contractual security obligations, customer due diligence, and independent audits rather than direct regulator penalties. Poor ACL control is still high risk: it raises the likelihood of unauthorized access, data leakage, and difficult incident scoping because you cannot quickly prove who had access to what. (CIS Controls v8)

Practical 30/60/90-day execution plan

First 30 days (stabilize scope and ownership)

• Publish the control card: owner, scope definition, triggers, exceptions, and evidence list. (CIS Controls v8)
• Build the initial inventory of in-scope repositories and name data owners.
• Pick two “crown jewel” repositories and export current ACLs as a baseline.
• Implement “ticket required” for new access to those repositories.

Days 31–60 (standardize and start operating)

• Write ACL standards for your main repository types (cloud storage, file shares, databases, core SaaS).
• Align change workflow: tickets, approvals, and logging expectations.
• Run the first formal access review for the crown jewels; open and track remediation items. (CIS Controls v8)
• Define how you will store evidence (folders, naming conventions, retention owner).

Days 61–90 (scale and make it repeatable)

• Expand inventory coverage to the next tier of repositories (departmental systems, analytics, collaboration).
• Automate permission exports where possible, and schedule drift checks.
• Run a second review cycle on the first repositories to prove repeatability.
• Add control health checks: completeness of reviews, open findings aging, and evidence quality. (CIS Controls v8)

If you need to operationalize quickly across many systems, Daydream’s value is keeping the control card, inventory, review cadence, and evidence bundles tied together so you can answer auditor questions without a scramble.

Frequently Asked Questions

What counts as an “ACL” for Safeguard 3.3?

Any permission mechanism that determines which identities can access a data repository qualifies, including filesystem ACLs, cloud IAM/bucket policies, database grants, and SaaS workspace permissions. You should document which mechanism applies per repository. (CIS Controls v8)

Do we need to review every single folder, table, or object?

Start with repository-level controls and your highest-risk datasets, then drill down where fine-grained permissions exist or where the data classification demands it. Define the review scope explicitly and follow it consistently. (CIS Controls v8)

How do we handle third-party managed systems where we cannot see full ACL detail?

Treat visibility as part of your scope decision: require permission reporting in the contract or compensating controls (e.g., restricted admin access, strong authentication, audit log access) and document the limitation as an exception with an owner. (CIS Controls v8)

What evidence is strongest for audits: screenshots or exports?

Exports or system-generated reports are stronger because they are easier to validate and compare over time. If you must use screenshots, pair them with the ticket ID, date, reviewer, and a brief review record. (CIS Controls v8)

Can we satisfy 3.3 with “access is controlled by Active Directory groups”?

Group-based access is fine if the underlying repositories enforce those groups through explicit ACLs and you review group membership and repository permissions. Auditors will still ask for proof of effective access at the data layer. (CIS Controls v8)

What’s the fastest way to reduce risk if we suspect overbroad access today?

Identify the highest-sensitivity repositories, export current permissions, remove public/anonymous access paths, and require approvals for any broad groups. Record what changed and why so you can show control operation later. (CIS Controls v8)