At what level do security groups provide protection?

Security groups in AWS function as virtual firewalls that control inbound and outbound traffic to AWS resources, specifically at the instance level. They are associated with Amazon EC2 instances and help in specifying which IP addresses, port ranges, and protocols allow or deny traffic to those instances. This means that they provide protection at the level of individual instances and the resources directly associated with them.

By allowing users to define rules that dictate traffic flow, security groups enhance the security posture of each instance. They operate based on stateful rules; for instance, if you allow incoming traffic on a specific port, the response traffic is automatically permitted. This level of control ensures that security groups specifically focus on securing the resources they are attached to, which are primarily EC2 instances and their associated resources.

The other options, while touching on security aspects, do not accurately capture the specific role of security groups in the AWS environment. Networks and applications encompass a broader scope and include components like VPCs and network ACLs, which are distinct from the instance-specific control security groups provide. Data storage security might involve other controls, such as IAM policies or S3 bucket policies, rather than being a direct function of security groups. Lastly, API call security is generally managed through IAM permissions and roles