A web application firewall that protects against common attacks such as SQL injection, XSS, and malicious bots. It integrates with CloudFront, ALB, and API Gateway through customizable rules.
This shows up as a layer 7 security tool on CLF-C02. SAA-C03 covers configuring rules. Difference from security groups (layer 4): WAF operates at the HTTP/HTTPS level and inspects request content.
AWS WAF (Web Application Firewall) is a concept that can show up on the exam. Check the full guide to see it in context.