Comment by throw0101c
11 hours ago
> I think having multiple authoritative DNS servers in different networks might help with this.
For the case of the dns-01 challenge type, sure. But if you're using http-01 (or the attacker asks for it), then all those DNS servers will answer back with the same IP address for the A(AAA) query and you're back to the hijacking scenario.
> http-01
Good point, I forgot about that! But then CAA record might help, I guess, if you specify your accounturi?
The attacker could hijack the network and initiate the ACME protocol against the CA in the CAA field. There is a draft for dns-account-01 which allows one to specify an ACME account which is authorized for updates (which uses the account key (and not cert key)):
* https://datatracker.ietf.org/doc/html/draft-ietf-acme-dns-ac...
haven't heard about dns-account-01, thanks! Heard only about dns-persist-01.
I meant to say that CAA record can also specify account, or at least Let’s Encrypt docs mention it[1]. So unless attacker has access to victim's account - they can't get a cert (unless they can hijack dns, too).
[1]: https://letsencrypt.org/docs/caa/#the-accounturi-parameter
1 reply →
http-01 seems absolutely unreliable, any hosting provider or any government can issue fake certificates using it. What a garbage technology.
The point is to prove you control a domain. If you are answering traffic to requests from clients at that domain, you control it. Whether you're supposed to have control over it is outside the scope of this validation
Agreed. On the other hand, these DV certificates only claim to verify who _controls_ the domain. Probably, you can agree that hosting provider and government can also control the domain, no? :)
Moreover, with dns-01, DNS provider can issue fake certificates - unless you self-host DNS - in which case, only your DNS registrar can... and a government.
> Moreover, with dns-01, DNS provider can issue fake certificates - unless you self-host DNS - in which case, only your DNS registrar can... and a government.
Which is what DNSSEC is supposed to help with: the registrar/government would have to replace your DS/KSK with their own. Without DNSSEC queries/replies could potentially be altered over the wire (or you're in a race condition as to whether the real or attacker's reply get back first).