In this ultimate how to implement guide to ISO 27001 Annex A 5.23 Information Security for Use of Cloud Services, you will learn directly from an ISO 27001 Lead Auditor:
- The requirement of the control
- The required implementation steps
- The minimum requirement
I am Stuart Barker, the ISO 27001 Lead Auditor and author of the Ultimate ISO 27001 Toolkit.
Using over 30 years of industry experience across hundreds of audits, I’m giving you the exact templates, walkthroughs, and practical examples you need to achieve ISO 27001 certification.
Table of contents
- ISO 27001 Annex A 5.23 Information Security for Use of Cloud Services Implementation Checklist
- 1. Establish a Custom Cloud Usage Policy
- 2. Mandate Specific Security Requirements in Cloud Contracts
- 3. Define and Document the Shared Responsibility Matrix
- 4. Implement Hardened Configuration Standards (IaC)
- 5. Enforce Strict Data Residency Controls
- 6. Verify Cloud Provider Independent Audit Evidence
- 7. Establish a Manual Cloud Exit Strategy
- 8. Configure Multi-Factor Authentication (MFA) for All Administrative Access
- 9. Monitor Cloud Activity via Local Log Aggregation
- 10. Perform Manual Change Management for Cloud Infrastructure
- ISO 27001 Annex A 5.23 SaaS / GRC Platform Implementation Failure Checklist
Implementing ISO 27001 Annex A 5.23 is the governance process of managing information security for cloud service adoption and lifecycle. The primary implementation requirement involves defining specific contractual mandates and shared responsibility models, providing the business benefit of mitigating third-party infrastructure risks through verifiable technical controls.
ISO 27001 Annex A 5.23 Information Security for Use of Cloud Services Implementation Checklist
Use this implementation checklist to achieve compliance with ISO 27001 Annex A 5.23. True cloud security is managed through hardened configuration files and specific contractual mandates, not by staring at a high-level compliance dashboard.
1. Establish a Custom Cloud Usage Policy
Control Requirement: Define and communicate organisational processes for the acquisition, use, management, and exit of cloud services.
Required Implementation Step: Open your word processor and draft a policy that specifies exactly which cloud service models (IaaS, PaaS, SaaS) are permitted and the mandatory security configurations for each. Manually distribute this to all department heads and obtain a physical or timestamped digital signature of receipt.
Minimum Requirement: A signed policy document that explicitly forbids the use of unapproved “Shadow IT” cloud services.
2. Mandate Specific Security Requirements in Cloud Contracts
Control Requirement: Ensure agreements with cloud service providers address information security risks.
Required Implementation Step: Review your current Cloud Service Agreements (CSAs). Manually negotiate or attach an addendum that specifies your requirements for data residency, encryption key management, and incident notification windows, rather than accepting the provider’s standard “click-through” terms.
Minimum Requirement: Evidence of a contract review or addendum addressing data jurisdiction and breach notification for all critical cloud vendors.
3. Define and Document the Shared Responsibility Matrix
Control Requirement: Clearly define the security roles and responsibilities between the organisation and the cloud provider.
Required Implementation Step: Create a physical table for each cloud service. Explicitly mark who is responsible for OS patching, application security, and identity management; do not assume the vendor “handles everything” just because they are a Tier 1 provider.
Minimum Requirement: A documented Shared Responsibility Model signed off by the Head of IT for every core cloud platform (e.g., AWS, Azure, M365).
