Which action can a company implement using security groups in AWS?

Security groups act as a virtual firewall for EC2 instances, controlling inbound and outbound traffic. They are stateful, meaning if you allow an outbound request, the return traffic is automatically allowed. A key function is to specify which ports and IP addresses are permitted to access an instance. Therefore, allowing access to an EC2 instance through only a specific port is a direct application of security groups. Denying access to malicious IP addresses at a subnet level is typically handled by Network Access Control Lists (NACLs), which are stateless and operate at the subnet level. Protecting data cached by Amazon CloudFront involves CloudFront security features like signed URLs/cookies or WAF, not security groups. Applying a stateless firewall to an Amazon EC2 instance describes NACLs, not security groups, which are stateful.