Securing EC2 Instance

When setting up an EC2 instance with Caddy as a reverse proxy to a Rack app, along with PostgreSQL and Redis, you should follow security best practices to protect your instance and the services running on it. Here are some recommendations for configuring the network and securing your EC2 instance:

1. Security Group Configuration:

   • Create a separate security group for your EC2 instance.
   • Allow inbound HTTP (port 80) and HTTPS (port 443) traffic from the desired source (e.g., anywhere or specific IP ranges) to enable access to your web application through Caddy.
   • Allow inbound SSH (port 22) traffic only from trusted IP ranges or use a bastion host for secure access.
   • Restrict inbound traffic to PostgreSQL (default port 5432) and Redis (default port 6379) to only the necessary sources, such as the EC2 instance itself or other trusted instances.
   • Block all other inbound traffic by default.

2. Network ACLs:

   • Configure Network ACLs (NACLs) as an additional layer of security at the subnet level.
   • Set up inbound and outbound rules in the NACLs to further control traffic flow to and from your EC2 instance.
   • Ensure that the NACLs allow the necessary traffic for your web application, PostgreSQL, and Redis while blocking unwanted traffic.

3. Private Subnet:

   • Consider launching your EC2 instance in a private subnet within a Virtual Private Cloud (VPC).
   • A private subnet does not have direct internet access and provides an additional layer of security.
   • Use a NAT Gateway or NAT Instance in a public subnet to enable outbound internet access for your EC2 instance in the private subnet when required.

4. Encryption:

   • Enable encryption for data at rest and in transit.
   • Use HTTPS with SSL/TLS certificates for secure communication between clients and your web application through Caddy.
   • Enable encryption for PostgreSQL connections to protect sensitive data.
   • If you have sensitive data in Redis, consider enabling authentication and encrypting Redis traffic using SSL/TLS.

5. Regular Updates and Patches:

   • Keep your EC2 instance and all the installed software (including Caddy, Rack, PostgreSQL, and Redis) up to date with the latest security patches and updates.
   • Regularly monitor for any security vulnerabilities and apply necessary patches promptly.

6. Access Management:

   • Use strong and unique passwords for all the services running on your EC2 instance.
   • Limit access to PostgreSQL and Redis to only the necessary user accounts with appropriate permissions.
   • Consider using IAM roles to manage access to AWS services and resources instead of using access keys.

7. Monitoring and Logging:

   • Enable monitoring and logging for your EC2 instance and the services running on it.
   • Use Amazon CloudWatch or other monitoring tools to track system metrics, logs, and potential security events.
   • Set up alerts and notifications for any suspicious activities or anomalies.

Regularly review and update your security configurations to ensure the ongoing protection of your EC2 instance and the services running on it. It’s also a good practice to conduct periodic security assessments and audits to identify and address any potential vulnerabilities.