Remediating new DNSSEC resource exhaustion vulnerabilities

Cloudflare has been part of a multivendor, industry-wide effort to mitigate two critical DNSSEC vulnerabilities. These vulnerabilities exposed significant risks to critical infrastructures that provide DNS resolution services. Cloudflare provides DNS resolution for anyone to use for free with our public resolver 1.1.1.1 service. Mitigations for Cloudflare’s public resolver 1.1.1.1 service were applied before these vulnerabilities were disclosed publicly. Internal resolvers using unbound (open source software) were upgraded promptly after a new software version fixing these vulnerabilities was released.

All Cloudflare DNS infrastructure was protected from both of these vulnerabilities before they were disclosed and is safe today. These vulnerabilities do not affect our Authoritative DNS or DNS firewall products.

All major DNS software vendors have released new versions of their software. All other major DNS resolver providers have also applied appropriate mitigations. Please update your DNS resolver software immediately, if you haven’t done so already.

Background

Domain name system (DNS) security extensions, commonly known as DNSSEC, are extensions to the DNS protocol that add authentication and integrity capabilities. DNSSEC uses cryptographic keys and signatures that allow DNS responses to be validated as authentic. DNSSEC protocol specifications have certain requirements that prioritize availability at Continue reading