They should map each service model to explicit customer responsibilities for identity, configuration, data protection, and logging. In SaaS the provider manages more of the stack, but the customer still owns access, data handling, and the configuration choices that commonly drive incidents.
How cloud responsibility maps to ownership decisions
The shared responsibility model only tells you where the provider’s duty stops and yours begins; it does not decide ownership for you. Organisations still have to assign an internal owner for each control area, because incidents usually happen at the seams, where a service is technically managed by the cloud vendor but the customer controls the settings, identities, and data paths.
That is why the practical question is not “who runs the service?” but “who can change the exposure?” If your team can alter access policy, encryption choices, network reachability, or logging, then your team owns the risk decisions tied to those settings, even when the underlying platform is operated by the provider.
This is also where accountability matters. A responsibility matrix should name the business owner, the technical owner, and the operational control owner for each service model, so that configuration, evidence, and exception handling do not get lost in vendor language.
What organisations usually own in SaaS, PaaS, and IaaS
In SaaS, the provider generally owns the application stack, uptime, and platform security, while the customer typically owns users, access policy, data classification, retention choices, and the configuration that governs sharing, external exposure, and auditability. In other words, SaaS reduces infrastructure burden, but it does not remove the customer’s responsibility for how the service is used.
In PaaS, the customer owns more of the application layer and the security of what they build on top of the platform. That includes application configuration, secrets handling, deployment settings, and the way the application authenticates and authorises access to data and downstream services.
In IaaS, the customer owns the broadest range of security decisions because they operate the operating system, the workload, the data, and most of the control plane configuration. The provider supplies the underlying infrastructure, but the customer decides how it is hardened, segmented, monitored, and integrated into the wider environment.
Most organisations make ownership decisions by asking three questions for each layer: who can change it, who can observe it, and who can prove it is working. That simple test often reveals that the “customer responsibility” is not just one team’s job, but a chain of duties across identity, security engineering, operations, and compliance.
Which controls need explicit owners, not just shared assumptions
Identity, configuration, data protection, and logging are the most common control areas that need explicit ownership because they are shared in practice even when the cloud provider supplies the technology. The customer may not manage the hypervisor, but it still owns the access model, the tenant configuration, and the data governance decisions that determine whether a misconfiguration becomes an incident.
For identity and access, ownership usually sits with the team that governs user access, privileged access, and federation, because access to cloud resources is often the fastest route to material impact. For configuration, ownership belongs to the team that can change security posture, whether that is a platform team, a cloud centre of excellence, or the application team with deployment rights.
For data protection and logging, ownership must be assigned to whoever can set the retention, sensitivity, encryption, and monitoring requirements, and who can respond when logs reveal suspicious activity. If no one owns those decisions, organisations end up with shared responsibility in theory and no responsibility in practice.
Organisations often formalise this through control mapping, service catalogues, and exception registers. A useful outcome is not a long policy document, but a clear statement of who approves risk acceptance, who remediates misconfiguration, and who supplies evidence when auditors or incident responders ask what happened.
Risk and Threat Considerations
Cloud ownership breaks down when teams assume the provider is responsible for security outcomes that are actually driven by customer configuration and access decisions. The main exposure is misattribution of control, which leaves identity, data, and logging gaps unowned until an incident forces clarification.
Failure mechanism: A customer leaves access paths, insecure defaults, overly broad permissions, or weak logging in place because no internal team has been assigned clear authority to change them, review them, and prove they are monitored.
Impact: The organisation can suffer unauthorised access, poor incident visibility, delayed containment, and audit failure, even though the underlying cloud service itself was operating as designed.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
NIST SP 800-53 Rev 5 and NIST CSF 2.0 set the technical controls, while ISO/IEC 27001:2022 defines the regulatory obligations.
| Framework | Control / Reference | Relevance |
|---|---|---|
| NIST SP 800-53 Rev 5 | AC-2 — Account Management | Cloud ownership depends on clear responsibility for access control and account administration. |
| CM-2 — Baseline Configuration | The model hinges on who owns secure configuration choices that drive cloud incidents. | |
| AU-2 — Event Logging | Logging ownership is central because monitoring duties still sit with the customer in shared responsibility. | |
| Recommendation — Assign explicit account ownership and approval responsibility for cloud users and privileged roles. Define and maintain approved cloud configuration baselines with named change owners. Set logging ownership, retention, and review responsibilities for each cloud service. | ||
| ISO/IEC 27001:2022 | A.5.15 — Access control | Cloud responsibility mapping must assign who governs access decisions and permissions. |
| A.8.9 — Configuration management | Ownership decisions depend on who controls secure configuration settings in the tenant. | |
| A.8.15 — Logging | Customers still own the logging choices needed to detect and investigate cloud incidents. | |
| Recommendation — Document access ownership and approval paths for each cloud service and tenant. Maintain controlled cloud configuration baselines and assign change ownership clearly. Define log collection, retention, and review ownership for cloud platforms and workloads. | ||
| NIST CSF 2.0 | PR.AA-01 — Identities and credentials are issued, managed, verified, revoked, and audited for authorized users, services, and devices. | Identity ownership is a core shared-responsibility decision in cloud environments. |
| PR.DS-01 — Data-at-rest is protected. | Data protection ownership remains with the customer even when the provider hosts the service. | |
| Recommendation — Assign lifecycle ownership for cloud identities and credentials across service models. Assign data protection ownership and enforce encryption and handling requirements. | ||
Practitioner Guidance
What to prioritise: Start with the controls that most often create actual loss, identity, configuration, data handling, and logging. If ownership is clear for those four areas, the rest of the shared responsibility discussion usually becomes much easier to operationalise.
What to verify: For each cloud service, verify that one team can answer three questions without ambiguity: who approves access, who changes the configuration baseline, and who investigates evidence when something goes wrong. If those answers differ by service model, document the difference rather than forcing one generic policy.
Common mistake: Treating the provider’s SLA or compliance attestation as proof that the customer has no remaining security work. The provider may secure the platform, but the customer still owns the choices that most often determine tenant compromise and data exposure.
Practitioner takeaway: Shared responsibility becomes useful only when translated into named control ownership, because cloud risk is usually created by the boundary between provider-managed infrastructure and customer-controlled security decisions.
Related resources from NHI Mgmt Group
- What should organisations do when the cloud shared responsibility model makes data protection harder to assign to one team?
- What happens when cloud teams do not audit access privileges under the shared responsibility model?
- Who should own cloud data security in organisations with shared responsibility across security, infrastructure, and development teams?
- How should organisations decide whether their multi-cloud identity model is working?