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> In a DNSSEC/DANE world, if you have a .LY name, the government of Libya would have a say in what your TLS certs were. Please explain to me how this would be

by danyork 12y ago

> In a DNSSEC/DANE world, if you have a .LY name, the government of Libya would have a say in what your TLS certs were. Please explain to me how this would be possible? - I sign my .LY domain with DNSSEC and create the appropriate DNSKEY and RRSIG records. - I create a DS record with a fingerprint of my DNSKEY and via my registrar (typically) upload this DS record to the TLD registry (.LY in this case). - Additionally, I create a TLSA record in my zone that holds my TLS cert and sign that with my key (creating the associated RRSIG record). When someone is querying DNS using a DNSSEC-validating DNS resolver, the resolver: ---- 1. Gets my DNS records (A, AAAA, MX, TLSA, whatever) from the authoritative name server for my domain (let's assume I operate it), along with the associated RRSIG and DNSKEY records. 2. Gets my DS record from the .LY registry, along with the RRSIG and the DNSKEY for the .LY registry. 3. Gets the DS record for .LY from the root zone, along with the RRSIG and the DNSKEY for the root zone. 4. Presumably has the root's trust anchor already stored. 5. Validates that my DNSKEY has the same fingerprint as that in the DS record received from the .LY registry - and walks back up the chain of trust to ensure that all DS records and DNSKEYs match. ---- Where in there can the government of Libya have a say in what TLS certs I offer? The best I could see is that the operator of the .LY registry could choose to modify or remove my DS record, which would then mean that my domain would fail DNSSEC validation. But the TLSA record is still coming from my site. All the .LY registry can do is potentially remove the link to the chain of trust. I really would like to know if I am missing something here.

tptacek 12y ago
The TLSA record is going to come from wherever the DNS hierarchy says it should come from.
- danyork 12y ago
  So to your point you would see the attack being that the .LY registry would change the NS records for my (fictitious) .LY domain to point to a different set of name servers? i.e. removing my servers as the authoritative ones? And then being able to serve out whatever records they want to? (including a TLSA) Is THAT the attack you see?
- makomk 12y ago
  The A or AAAA record is also going to come from wherever the DNS hierarchy says it should come from. If one of the organisations upstream from you in the DNS hierarchy decides they want to police what TLS certificates sites can use by hijacking the sites' DNS and pointing it to their own servers, they can do that just as easily regardless of whether those certificates come from DNS or the traditional CAs. Once they've hijacked the domain, any major CA will happily automatically issue them a valid certificate for it.

by danyork 12y ago

tptacek 12y ago

The TLSA record is going to come from wherever the DNS hierarchy says it should come from.

danyork 12y ago
So to your point you would see the attack being that the .LY registry would change the NS records for my (fictitious) .LY domain to point to a different set of name servers? i.e. removing my servers as the authoritative ones? And then being able to serve out whatever records they want to? (including a TLSA) Is THAT the attack you see?
makomk 12y ago
The A or AAAA record is also going to come from wherever the DNS hierarchy says it should come from. If one of the organisations upstream from you in the DNS hierarchy decides they want to police what TLS certificates sites can use by hijacking the sites' DNS and pointing it to their own servers, they can do that just as easily regardless of whether those certificates come from DNS or the traditional CAs. Once they've hijacked the domain, any major CA will happily automatically issue them a valid certificate for it.