Deciphering the Digital Veil: Exploring the Ecosystem of DNS HTTPS Resource Records

The DNS HTTPS resource record is a new DNS record type designed for the delivery of configuration information and parameters required to initiate connections to HTTPS network services. It provides the ability to perform zone apex redirection to a third-party provider, which the existing CNAME record cannot do. In addition, it is a key enabler for TLS Encrypted ClientHello (ECH) by providing the cryptographic keying material needed to encrypt the initial exchange. To understand the adoption and security of this new DNS HTTPS record, we perform a longitudinal study on the server-side deployment of DNS HTTPS for Tranco top 1 million domains over 8 months, as well as the client-side support for DNS HTTPS from major browsers. To the best of knowledge, our work is the first longitudinal study on DNS HTTPS server deployment, and the first known study on client-side support for DNS HTTPS. Despite the rapidly growing trend of DNS HTTPS adoption, our study highlights concerns in the deployment by both servers and clients, such as the complexity in properly maintaining HTTPS records and the concerning hardfail mechanisms in browser when using HTTPS records.