Use a Web Application Firewall (WAF) with an EC2 instance

Question

I have a web app running on my Amazon EC2 instance. How can I integrate a Web Application Firewall with my EC2?

I have tried setting up the WAF, but it can only be associated with either a CloudFront distribution or an Elastic Load Balancer. Do I need to setup a CloudFront distribution and point it at my EC2 instance?

Answer 1

I ended up setting up an elastic load balancer pointing to my single instance and then adding the web application firewall pointing to the load balancer. It works pretty well and doesn't cost too much more per month from AWS.

Answer 2

The two approaches you can connect AWS WAF to your EC2 instance through,

• AWS CloudFront
• Application Load Balancer (ALB)

Each approach has its own pros and cons. If your application servers more of content that can be cached, then having AWS CloudFront along with WAF. If your application cluster needs to scale but most of it is dynamic content then going for ALB is more reasonable.

Note: There is an added fixed cost for ALB (In addition to the variable cost which is not significant though) for each month while CloudFront cost is variable and consumption driven.

It is also possible to have both CloudFront and ALB together where you can add the WAF to CloudFront only.