One key to sign them all considered vulnerable: Evaluation of DNSSEC in the internet

We perform the first Internet study of the cryptographic security of DNSSEC-signed domains. To that end, we collected 2:1M DNSSEC keys for popular signed domains out of these 1:9M are RSA keys. We analyse the RSA keys and show that a large fraction of signed domains are using vulnerable keys: 35% are signed with RSA keys that share their moduli with some other domain and 66% use keys that are too short (1024 bit or less) or keys which modulus has a GCD > 1 with the modulus of some other domain. As we show, to a large extent the vulnerabilities are due to poor key generation practices, but also due to potential faulty hardware or software bugs. The DNSSEC keys collection and analysis is performed on a daily basis with the DNSSEC Keys Validation Engine which we developed. The statistics as well as the DNSSEC Keys Validation Engine are made available online, as a service for Internet users.