Security & Quality

Cloudflare WAF Protection

Configure Cloudflare Web Application Firewall rules to protect against SQL injection, XSS, and DDoS attacks.

Claude Code Cursor

Overview

Cloudflare WAF (Web Application Firewall) provides enterprise-grade protection against web application attacks at the edge. It inspects incoming HTTP requests and blocks malicious traffic before it reaches your origin server. The WAF includes managed rulesets from Cloudflare, OWASP Core Rule Set, and custom rules that you define using the wirefilter expression language.

Cloudflare WAF operates at multiple layers: managed rules handle known attack patterns (SQLi, XSS, RCE, file inclusion), rate limiting rules prevent brute force and DDoS attacks, and custom rules allow you to create business-specific protections. The WAF also includes Bot Management to distinguish between legitimate bots (search engines) and malicious automated traffic.

Configuration can be managed through the Cloudflare dashboard, API, or Infrastructure as Code tools like Terraform and Pulumi. The Wrangler CLI allows developers to manage WAF rules programmatically. Cloudflare's analytics provide visibility into blocked attacks, top attack vectors, and geographic distribution of malicious traffic.

Who Is This For?

Block SQL injection and XSS attacks at the edge
Set up DDoS protection rules for public APIs
Configure country-based access restrictions
Create custom WAF rules for application-specific threats

Installation

Setup for Claude Code

npm install wrangler -g

Configuration

// Cloudflare WAF custom rule (wirefilter expression)
// Block SQL injection attempts
// (http.request.uri.query contains "UNION SELECT" or
//  http.request.uri.query contains "DROP TABLE" or
//  http.request.body.raw contains "'; --")

// wrangler CLI to manage rules
// wrangler deploy --config wrangler.toml

// Terraform example
// resource "cloudflare_ruleset" "waf_custom" {
//   zone_id = var.zone_id
//   name    = "Custom WAF rules"
//   kind    = "zone"
//   phase   = "http_ratelimit"
// }