In the AWS shared responsibility model, AWS is responsible for protecting the infrastructure that runs AWS services in the AWS Cloud, while the customer is responsible for securing the data they put into the cloud services and the configurations of the services they use. In this scenario, configuring security groups correctly is under the customer’s purview as part of 'Security in the Cloud.' Security groups act as a virtual firewall for instances to control inbound and outbound traffic. Patch management of the EC2 instances, including the operating system, is also a customer responsibility, but more related to managing the guest OS, not directly related to the application they are running. Protecting the underlying infrastructure (data centers, hardware, etc.) and disaster recovery for AWS services are AWS’s responsibility.