Information Security for Use of Cloud Services

It is an organizational control requiring established processes for the acquisition, use, management, and exit from cloud services to ensure they align with the organization's information security requirements.

Implement by defining security baselines (e.g., CIS benchmarks), configuring Identity and Access Management (IAM) correctly, enabling logging (CloudTrail/Log Analytics), and regularly reviewing the provider's security compliance (Shared Responsibility Model). Tools like WatchDog Security's Posture Management can continuously assess configurations against your baseline and surface misconfigurations for remediation.

It should include criteria for selecting cloud providers, acceptable use rules, requirements for encrypting data at rest/transit, defined roles for the shared responsibility model, and procedures for service termination.

Auditors expect a Third-Party Management Policy, a Vendor Inventory listing cloud services, evidence of vendor security reviews (due diligence), and signed agreements or terms of service. WatchDog Security's Compliance Center can map A.5.23 evidence expectations and track collection status, while WatchDog Security's Vendor Risk Management can maintain the Vendor Inventory and vendor review records in a structured workflow.

Conduct a risk assessment considering the classification of data to be stored, regulatory requirements (like GDPR), availability needs, and required technical controls (like SSO support) before purchase.

Review the provider's third-party audit reports (SOC 2 Type II, ISO 27001), analyze the shared responsibility model to identify gaps, and monitor their security advisories regularly.

An exit strategy is a documented plan for migrating data away from a cloud provider; meeting requirements involves ensuring contracts allow for data retrieval and deletion upon termination to prevent lock-in.

Document specific responsibilities (e.g., provider manages hardware, you manage OS patching and user access) in the Vendor Security Review or Risk Assessment for each major cloud platform.

Yes, if your risk assessment or policy deems them necessary controls; A.5.23 requires alignment with your organization's security requirements, which typically mandate these technical measures.

ISO 27001 is the primary certification standard for the ISMS; ISO 27017 is a code of practice providing specific guidance on implementing cloud security controls and should be used to support your ISO 27001 implementation.

A.5.23 expects you to control cloud service acquisition and ongoing use, which is difficult if teams can self-provision apps. Start by defining what must be approved (data types, SSO/MFA, logging, residency) and maintaining a living inventory of cloud and SaaS services. WatchDog Security's Asset Inventory helps discover and map cloud/SaaS assets and identities so you can detect unapproved services and keep your inventory current for audits and reviews.

Because cloud settings change frequently, one-time reviews can miss drift from your baseline (e.g., logging disabled, overly permissive IAM, exposed storage). Define your baseline (such as CIS-aligned expectations) and monitor for deviations with clear remediation ownership. WatchDog Security's Posture Management can detect misconfigurations across cloud environments, and WatchDog Security's Compliance Center can link those findings to A.5.23 evidence and control status.