Rule: Amazon EC2 Should Be Configured to Use VPC Endpoints

This rule enforces the use of VPC endpoints for AWS Foundational Security Best Practices in Amazon EC2 instances. VPC endpoints allow secure and private communication between resources within a VPC and AWS services without the need for internet access.

By configuring VPC endpoints, you can prevent unnecessary exposure of sensitive data and resources to the public internet. It ensures that all communication between EC2 instances and AWS services remains within the internal network, offering improved security and reduced data transfer costs.

To remediate this, follow the steps below:

1.1. Identify the VPC(s) linked to the EC2 instances in question.

1.2. Determine if any EC2 instances are communicating with AWS services over the public internet.

1.3. Check if VPC endpoints are already configured for the required AWS services.

2.1. Log in to AWS Management Console.

2.2. Open the Amazon VPC service.

2.3. Select the target VPC for which you want to create VPC endpoints.

2.4. Click on the "Endpoints" section in the left navigation pane.

2.5. Click "Create Endpoint" and select the desired service from the list (e.g., S3, DynamoDB).

2.6. Configure the endpoint settings, including VPC route tables and security groups.

2.7. Review and create the endpoint.

2.8. Repeat steps 2.5 to 2.7 for each required AWS service.

3.1. Identify the security groups associated with the EC2 instances.

3.2. Navigate to the Amazon VPC service in the AWS Management Console.

3.3. Select the Security Groups section from the left navigation pane.

3.4. Select the relevant security group(s) associated with the EC2 instances.

3.5. Update the inbound and outbound rules as needed to allow communication through the VPC endpoints.

4.1. Connect to the EC2 instances currently communicating with AWS services.

4.2. Validate that the applications/services on the instances can communicate with the required AWS services.

4.3. Ensure that there are no disruptions in functionality or performance.

• If communication fails after configuring VPC endpoints, ensure that the correct service and endpoint configurations are in place.
• Check if any network ACLs or AWS Identity and Access Management (IAM) policies are blocking the communication.
• Verify that the EC2 instances have the necessary permissions to access the VPC endpoints.
• Look for any DNS resolution issues. Ensure that the DNS settings on the EC2 instances are correctly configured.
• If the issue persists, review CloudWatch logs, VPC flow logs, and other relevant monitoring tools to diagnose and troubleshoot further.

• Regularly review and update VPC endpoints as new services are added or requirements change.
• Ensure that all required security patches and updates are applied to the EC2 instances and associated services.

• AWS VPC Endpoint Documentation