Shared Responsibility Model

The shared responsibility model is a foundational concept in cloud security that defines the division of security duties between a cloud service provider (CSP) and the customer. While the specifics vary by provider, the general principle remains consistent: the provider secures the underlying infrastructure, and the customer secures what they deploy on top of it.

In an Infrastructure as a Service (IaaS) model, the provider is responsible for physical data centers, networking hardware, and the hypervisor layer. The customer is responsible for the operating system, applications, data, and identity management. In Platform as a Service (PaaS) and Software as a Service (SaaS) models, the provider takes on progressively more responsibility, but the customer always retains responsibility for their data and access controls.

Misunderstanding the shared responsibility model is a leading cause of cloud security incidents. Organizations frequently assume the cloud provider handles all security concerns, leaving critical gaps in areas like data encryption, access management, and network configuration. Security teams must clearly map responsibilities, implement appropriate controls for their side of the model, and regularly validate that both parties are fulfilling their obligations through audits and compliance checks.