ISO/IEC 27017.

What ISO/IEC 27017 actually adds

ISO/IEC 27017 is not a standalone certification scheme. It is a code of practice that sits on top of ISO/IEC 27002, the implementation guidance for ISO/IEC 27001 controls. Where 27002 describes a generic information security control, 27017 adds cloud-specific implementation guidance for that same control, and in some places it introduces additional controls that only make sense once your data lives on infrastructure you do not own. So when you adopt it, you are not running a parallel ISMS. You are extending the one you already certify against ISO 27001 so that it speaks the language of cloud.

The practical value is that it forces both sides of the cloud relationship to write things down. The standard is deliberately structured so that each piece of guidance has a version for the cloud service provider and a version for the cloud service customer. That dual framing is the whole point. A control like access management or cryptographic key handling means something different depending on whether you are the hyperscaler running the platform or the tenant deploying workloads onto it, and 27017 makes that split explicit instead of leaving it to assumption.

Shared responsibility, made auditable

Every cloud security conversation eventually lands on shared responsibility: the provider secures the infrastructure, the customer secures what they put on it. The trouble is that the boundary moves depending on the service model. With infrastructure as a service the customer owns the operating system, patching, and most configuration. With software as a service almost everything sits with the provider, and the customer is mostly left with identity, access, and data governance. ISO 27017 turns that fuzzy diagram into something an auditor can test.

• It asks the provider to document which security responsibilities they retain and which they hand to the customer, so there is no silent gap.
• It asks the customer to confirm they understand and have actually implemented their share, rather than assuming the provider covers it.
• It adds guidance specific to multi-tenant environments, virtual machine hardening, administrative operations, and the segregation of customers running on shared hardware.
• It addresses removal and return of assets when a contract ends, which is where many cloud exits go wrong.

Where it sits next to its neighbours

27017 is easy to confuse with the standards around it, so it helps to keep the family clear. ISO/IEC 27001 is the certifiable management system. ISO/IEC 27002 is the general control guidance. ISO/IEC 27017 is the cloud security extension of that guidance. ISO/IEC 27018 is the sibling that focuses specifically on protecting personally identifiable information in public cloud, which matters when your cloud workloads also carry personal data and you are answering to privacy obligations alongside security ones.

For a practitioner the workflow is consistent. You run an ISO 27001 ISMS, you bring cloud workloads into its scope, and you use 27017 to decide which cloud controls you map and how you evidence both sides of the responsibility line. If those workloads also process personal data, you pair it with 27018. None of these replace your contractual due diligence on the provider; they give you a structured way to prove you did it.