Web Application Firewall: AWS WAF as the First Line of Defense

Why a WAF Is Indispensable

No matter how secure your code is — attacks will come. SQL injection, XSS, credential stuffing, and layer 7 DDoS attacks are everyday occurrences. A WAF filters these attacks before they reach your application.

AWS WAF: Features

• Managed Rules: Predefined rule sets from AWS and partners for OWASP Top 10, known bad inputs, and bot control.
• Rate Limiting: Limit requests per IP or per session — prevents brute-force and minor DDoS attacks.
• Geo Blocking: Block traffic from regions that are not relevant to your business.
• Custom Rules: Custom rules based on header, body, query string, or IP — for application-specific protection mechanisms.

Integration with CloudFront

AWS WAF sits in front of CloudFront and filters requests at the edge. This means: attacks are blocked globally before they reach your origin servers. The latency impact is minimal — under 1 ms per request.

Best Practices

• Count Mode First: Deploy new rules in count mode, analyze logs, then switch to block.
• Logging: Send WAF logs to S3 or CloudWatch for forensic analysis.
• Automation: Automatically update IP blacklists based on threat intelligence feeds.