3 ms·

I don’t quite follow why a missing underscore results in a security problem. It seems like it must be somehow related to what’s valid for CNAME records?

• aaomidi 2y ago
  For DNS managers, it’s a known thing to restrict the use of domains that start with _. It’s effectively a reserved keyword. In this case, a sophisticated attacker can get certificates for domains they don’t control by abusing this.
  • jtc331 2y ago
    Thanks, that’s helpful information.