A company operates a workload in a single AWS VPC. The architecture includes several interface VPC endpoints for AWS services (for example, Amazon CloudWatch Logs and AWS KMS). All endpoints use the same security group, which is not attached to any other resources. A security review found the shared security group is overly permissive. The company wants to tighten the security group rules but must not break access from VPC resources to AWS services via the interface endpoints. Current security group rules are:

Interface VPC endpoints are accessed from within the VPC. Therefore, allowing inbound TCP 443 from 0.0.0.0/0 (Inbound - Rule 1) is overly permissive as it allows access from outside the VPC, which is unnecessary for internal VPC resources. The Inbound - Rule 2 (TCP 443 from VPC CIDR) is sufficient for allowing VPC resources to communicate with the endpoints. Similarly, the Outbound - Rule 1 (All protocols/ports to 0.0.0.0/0) is overly permissive. While interface endpoints are typically stateless regarding outbound connections from the security group perspective, a more restrictive outbound rule aligned with the required services would be better practice if outbound rules were strictly enforced. However, for interface endpoints, the primary concern is inbound access. Removing Outbound - Rule 1 improves security posture by eliminating an overly broad outbound allowance. Removing only Outbound - Rule 2 is not an option provided. Removing Inbound - Rule 2 would break access.