A company is moving data center applications to Azure Virtual Machines. Under the Shared Responsibility Model for Infrastructure as a Service (IaaS), who is primarily responsible for patching the guest virtual machine's operating system?

In the Shared Responsibility Model for IaaS, the customer is primarily responsible for patching the guest operating system. Microsoft Azure is responsible for the physical infrastructure, network controls, and the hypervisor. However, for IaaS virtual machines, the customer manages the operating system, applications, and data. This includes tasks like OS patching, security configurations within the OS, and application updates. The cloud provider (Microsoft Azure) is responsible for the underlying host OS and infrastructure patching, but not the guest OS. A third-party security vendor might assist, but the ultimate responsibility remains with the customer. While there's a shared aspect to security, specific responsibilities are clearly delineated, and guest OS patching falls squarely on the customer for IaaS.