CIS Controls v8 9.1 — Ensure Use of Only Fully Supported Browsers and Email Clients

What this control requires

Ensure only fully supported browsers and email clients are allowed to execute in the enterprise, only using the latest version of browsers and email clients provided through the vendor.

In plain English

Ensure only fully supported browsers and email clients are allowed to execute in the enterprise, only using the latest version of browsers and email clients provided through the vendor. In practice, this means you can prove you ensure version-level controls on a defined cadence.

Why it matters

The CIS Controls are an industry-vetted, prioritised defence: skipping a safeguard widens the attack surface that the safeguards above and below it assume is closed. Audit frameworks (FedRAMP, PCI DSS, HIPAA) all cite CIS as evidence of due care.

This control is rated critical in the source catalogue. Treat gaps here as production incidents in the risk register, not housekeeping.

What an auditor looks for

A CIS-aligned reviewer wants to see (a) which Implementation Group you are targeting, (b) a documented owner for the safeguard, and (c) a tooling or process artefact (config, scan output, ticket) that proves the safeguard runs on the cadence the control demands.

Within Protect, the assessor will trace your implementation back to the catalogue reference (Control 9.1) and look for objective evidence on the latest two assessment cycles.

How to implement

1. Write a short policy stating intent, scope and named owner.
2. Encode it as a platform guardrail — SCP, Azure Policy initiative, Organisation Policy, or repository policy.
3. Wire a monitoring signal that catches drift (CSPM rule, SIEM rule, scheduled query, Workspace alert) and ticket it.
4. Review on a documented cadence and capture the review in the risk register or compliance tracker.

Operational checklist

• Ensure. Document the trigger, the owner and the cadence.
• Ensure Use. Document the trigger, the owner and the cadence.
• Protect. Document the trigger, the owner and the cadence.
• Scope: version, email, enterprise.

Evidence to collect

• Vendor Risk Management. vendor_risk_management evidence

Third-party risk management evidence (assessments, contracts, due diligence) shows supplier oversight. Focus: Ensure Use of Only Fully Supported Browsers and Email Clients.

How it maps to other frameworks

Computed from shared tags, control component and key-operation subjects — handy when you are reconciling controls across an audit.

• SOC 2 (2017 TSC) CC9.2 — Vendor Risk Management
• GDPR Article 76 — Confidentiality
• BSI C5:2020 OIS-03 — Interfaces and Dependencies
• ISO/IEC 27001:2022 A.5.20 — Addressing information security within supplier agreements
• ISO/IEC 42001:2023 A.10.2 — Allocation of responsibilities

Related controls in CIS Controls v8

• Control 16.5 — Use Up-to-Date and Trusted Third-Party Software Components
• Control 16.4 — Establish and Manage an Inventory of Third-Party Software Components
• Control 15.7 — Securely Decommission Service Providers
• Control 16.2 — Establish and Maintain a Process to Accept and Address Software Vulnerabilities
• Control 16.1 — Establish and Maintain a Secure Application Development Process
• Control 15.1 — Establish and Maintain an Inventory of Service Providers

References

• Center for Internet Security — CIS Controls v8
• Catalogue identifier: Control 9.1

Topics: vendor riskvendor managementsupply chain securitythird party monitoring