What is the AWS Web Application Firewall (WAF)?

• It enables the establishment of security rules aimed at managing bot activity and block common attack patterns like SQL injection or cross-site scripting."

• It is a AWS Managed service.

Enable AWS WAF and apply the rules using a Terraform module (2*)

1- Change <ADD_YOUR_IP> with your IP in the 03-aws-waf.tf

2- Run the following commands:

• terraform init

• terraform plan

• terraform apply

  • It will create a VPC, 2 subnets, 2 EC2 instances, 1 Load Balancer (3*)
  • following this, AWS WAF will be enabled and associated with the previously created Load Balancer.

3- Try to access the Load Balancer (using its DNS Name)

You will encounter a 403 Error, indicating that access is forbidden. This occurs because the IP address has been added to the block list within AWS WAF

Notes

1. It is not possible to attach WAF directly to a Classic Load Balancer (CLB), because it is not supported. If you have to do it then one option would be creating a CloudFront distribution that uses the CLB as the origin and then attaching WAF to CloudFront.(4*)

But it has some risks. When using CloudFront with a Classic Load Balancer (CLB) as the origin, communication is restricted to HTTP and HTTPS protocols only. This means that clients accessing your CloudFront distribution and the communication between CloudFront and the CLB will be limited to these protocols. However, you can specify a custom HTTP/HTTPS port for this communication if needed. (5*)

References

1* https://aws.amazon.com/waf/

2* https://github.com/trussworks/terraform-aws-wafv2

3* https://github.com/iam-veeramalla/aws-devops-zero-to-hero/tree/main/day-24

4* Options for WAF with a Classic Load Balancer

5* What risks should I expect when applying WAF to Classic Load Balancer with CloudFront?