[cabfpub] VWG Question 3 – Domain Validation pre-ballot

kirk_hall at trendmicro.com kirk_hall at trendmicro.com
Wed Nov 18 23:28:41 UTC 2015


Doug Beattie noted on the last call that the current definition of Authorization Domain Name already includes this text “The CA may prune zero or more labels from left to right until encountering a Base Domain Name and may use any one of the intermediate values for the purpose of domain validation.”, and Doug didn’t think Peter’s suggested edit was necessary.
Peter responded that “I agree that the current language of Line J [which is Method 7] makes my comment moot. “
From: Kirk Hall (RD-US)
Sent: Thursday, November 12, 2015 5:08 PM
To: CABFPub (public at cabforum.org)
Subject: Question 3 – Domain Validation pre-ballot

Question 3 – Domain Validation pre-ballot

Peter Bowen Comments

Peter Bowen of Amazon did not submit specific new language, but posed the following comment about new Method No. 7 shown below:

Proposal 3: In line J of current draft (Method No. 7)

“In Item J, it suggests that the random token is only valid for a FQDN validation.

“I think DNS validation should be allowed for domain hierarchies in addition to specific FQDNs.  A domain registrant should be able to choose to approve all FQDNs under corp.example.com<http://corp.example.com> by adding a record for corp.example.com<http://corp.example.com>.”


Here is the current Ballot language for Method No. 7:



“7. Having the Applicant demonstrate control over the requested FQDN by the Applicant making a change to information in a DNS record for an Authorization Domain Name where the change is to insert a Random Value or Request Token; or “

I noted we had discussed before the problem of “kirkstore.shopping.com” – Kirk might have control over the third level FQDN, but might not have control over the SLDN (Base Domain) of shopping.com, so even though Kirk could demonstrate control for kirkstore.shopping.com, he should not use that to get a cert for shopping.com.

Doug Beattie thought that Peter might be misreading Authorization Domain Name, which is defined as follows:

“Authorization Domain Name: The Domain Name used to obtain authorization for certificate issuance or a given FQDN. The CA may use the FQDN returned from a DNS CNAME lookup as the FQDN for the purposes of domain validation. If the FQDN starts with a wildcard character, then the CA MUST remove all wildcard labels from the left most portion of requested FQDN. The CA may prune zero or more labels from left to right until encountering a Base Domain Name and may use any one of the intermediate values for the purpose of domain validation.“

“Base Domain Name: The portion of an applied-for FQDN that is the first domain name node left of a registry-controlled or public suffix plus the registry-controlled or public suffix (e.g. “example.co.uk” or “example.com”). For gTLDs, the domain www.[gTLD<http://www.[gTLD>] will be considered to be a Base Domain. “

Questions for Discussion:

(1) Is Doug correct that the current definition of Authorized Domain Name (see underlined text above) would already satisfy Peter’s suggestion that proving control of any FQDN by making a change to the DNS record for that FQDN is sufficient to get a certificate for any lower level domain it contains, including the SLDN or Base Domain?   If yes, are any changes needed?

(2) More generally, do the members agree with Peter’s statement that “A domain registrant should be able to choose to approve all FQDNs under corp.example.com<http://corp.example.com> by adding a [DNS]record for  corp.example.com<http://corp.example.com>.”  If not, do we need to change the definition of Authorization Domain Name to delete the language underlined above?

To Peter Bowen: If you want to comment on this issue, please email to me and I will post to the Public list.


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