I put Cloudflare in front of my site, then found my origin one DNS record away from undoing it

Short summary

CDN protection like Cloudflare fails if attackers discover your origin IP through DNS history, certificate transparency logs, or forgotten subdomains. The author built origin-exposure-check, a Rust security tool that performs attacker-style discovery to audit whether your origin is reachable past your CDN. It enumerates candidate IPs, probes them while presenting the real hostname (bypassing DNS), and reports EXPOSED or CONTAINED. Remediation: restrict origin firewall to CDN IP ranges or use a private tunnel.

• •Origin IP exposure completely undermines CDN protection if attackers can find it
• •Certificate transparency logs, DNS history, and forgotten subdomains commonly leak origin IPs
• •origin-exposure-check (Rust, MIT) audits your infrastructure using the same discovery methods attackers would use

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