CloudFlair: Bypassing Cloudflare using Internet-wide scan data

Cloudflare is a service that acts as a middleman between a website and its end users, protecting it from various attacks. Unfortunately, those websites are often poorly configured, allowing an attacker to entirely bypass Cloudflare and run DDoS attacks or exploit web-based vulnerabilities that would otherwise be blocked. This post demonstrates the weakness and introduces CloudFlair, an automated detection tool.