Hardening Your AWS Infrastructure with WAF — A Practical Guide

Why WAF Matters

A Web Application Firewall inspects HTTP traffic before it reaches your application. It blocks malicious requests at the edge — SQL injection, XSS, DDoS floods — before they ever hit your EC2/EKS workloads.

Core Rule Groups I Applied

1. AWS Managed Rules

resource "aws_wafv2_web_acl" "main" {
  name  = "prod-waf"
  scope = "REGIONAL"

  rule {
    name     = "AWSManagedRulesCommonRuleSet"
    priority = 1
    override_action { none {} }
    statement {
      managed_rule_group_statement {
        name        = "AWSManagedRulesCommonRuleSet"
        vendor_name = "AWS"
      }
    }
  }
}

2. Rate Limiting

We capped requests at 2000 per 5 minutes per IP to neutralize brute force and credential stuffing.

3. Geo-blocking

Blocked traffic from regions we don't operate in, reducing noise by ~40%.

Impact