[cabfpub] Voting Begins: Ballot SC2 - version 2: Validating certificates via CAA CONTACT

Tim Hollebeek tim.hollebeek at digicert.com
Thu Jul 19 08:02:35 MST 2018


 

Administrivia:

 

1.	This ballot is being cross-posted to the CABF public mailing in line
with the consensus from last Thursday's call that it is important everyone
is aware of the ballot, and that not everyone is on the SCWG list yet.
2.	I promised an IETF independent stream draft for the same proposal,
so it can get feedback from those at IETF.  I still intend to do so, but I
am working with a colleague on setting up a github account for DigiCert IETF
efforts to make it easier for others to collaborate with us on IETF
submissions.  I anticipate we will have that set up and the draft submitted
some time next week.  The IETF draft will allow IETF to review the method
and make suggested improvements.  It should not block adoption of the
current proposal by CABF.  DigiCert intends to submit a ballot to adopt
IETF's improvements once the IETF process is complete.

 

Ballot SC2: CAA Contact Property and Associated Validation Methods

Purpose of Ballot: Increasingly, contact information is not available in
WHOIS due to concerns about potential GDPR violations.  This ballot
specifies a method by which domain holders can publish their contact
information via DNS, and how CAs can use that information for validating
domain control.

The following motion has been proposed by Tim Hollebeek of DigiCert and
endorsed by Bruce Morton of Entrust and Doug Beattie of GlobalSign.

--- MOTION BEGINS ---

This ballot modifies the "Baseline Requirements for the Issuance and
Management of Publicly-Trusted Certificates" as follows, based on Version
1.5.7:

Add Section 3.2.2.4.13: Domain Owner Email published in DNS

Confirm the Applicant's control over the FQDN by (i) sending an email to a
DNS domain name holder, (ii) including a Random Value in the email, and
(iii) receiving a confirming response utilizing the Random Value. The CA
MUST send the email to an email address found in the CAA Contact property
record as defined in Appendix B.

 

Each email MAY confirm control of multiple FQDNs, provided the email address
used is a DNS contact email address for each FQDN being confirmed. 

 

The Random Value SHALL be unique in each email. The email MAY be re-sent in
its entirety, including the re-use of the Random Value, provided that its
entire contents and recipient SHALL remain unchanged. The Random Value SHALL
remain valid for use in a confirming response for no more than 30 days from
its creation. The CPS MAY specify a shorter validity period for Random
Values.

Note: Once the FQDN has been validated using this method, the CA MAY also
issue Certificates for other FQDNs that end with all the labels of the
validated FQDN. This method is suitable for validating Wildcard Domain
Names.

Add Section 3.2.2.4.14: Domain Owner Phone published in DNS

 

Confirm the Applicant's control over the FQDN by calling the DNS domain name
holder phone number and obtaining a response confirming the Applicant's
request for validation of the FQDN. The CA MUST place the call to a phone
number identified in the CAA Contact property record as defined in Appendix
B.

 

Each phone call SHALL be made to a single number and MAY confirm control of
multiple FQDNs, provided that the phone number is identified by the DNS
contact as a valid contact method for every Base Domain Name being verified
using the phone call.

Note: Once the FQDN has been validated using this method, the CA MAY also
issue Certificates for other FQDNs that end with all the labels of the
validated FQDN. This method is suitable for validating Wildcard Domain
Names.

 

Add Section 3.2.2.4.15: Domain Owner Email published in TXT record

 

Confirm the Applicant's control over the FQDN by (i) sending an email to a
DNS domain name holder, (ii) including a Random Value in the email, and
(iii) receiving a confirming response utilizing the Random Value. The CA
MUST send the email to an email address found in the DNS TXT record as
defined in Appendix B.

 

Each email MAY confirm control of multiple FQDNs, provided the email address
used is a DNS contact email address for each FQDN being confirmed. 

 

The Random Value SHALL be unique in each email. The email MAY be re-sent in
its entirety, including the re-use of the Random Value, provided that its
entire contents and recipient SHALL remain unchanged. The Random Value SHALL
remain valid for use in a confirming response for no more than 30 days from
its creation. The CPS MAY specify a shorter validity period for Random
Values.

Note: Once the FQDN has been validated using this method, the CA MAY also
issue Certificates for other FQDNs that end with all the labels of the
validated FQDN. This method is suitable for validating Wildcard Domain
Names.

 

##### 3.2.2.4.16 Domain Owner Phone published in TXT record

 

Confirm the Applicant's control over the FQDN by calling the DNS domain name
holder phone number and obtaining a response confirming the Applicant's
request for validation of the FQDN. The CA MUST place the call to a phone
number identified in the DNS TXT record defined in Appendix B.

 

Each phone call SHALL be made to a single number and MAY confirm control of
multiple FQDNs, provided that the phone number is identified by the DNS
contact as a valid contact method for every Base Domain Name being verified
using the phone call.

Note: Once the FQDN has been validated using this method, the CA MAY also
issue Certificates for other FQDNs that end with all the labels of the
validated FQDN. This method is suitable for validating Wildcard Domain
Names.

Add Appendix B: CAA Contact Tag

The syntax for the contact property is similar to the iodef property.  It
allows domain owners to publish contact information in DNS in addition to
WHOIS for the purpose of validating domain control.

CAA contact Property

 

contact <URL> :  The contact property entry specifies the authorized means
of contacting the holder of the domain or another party who is authorized to
approve issuance of certificates for the domain.

 

The contact property specifies a means of contacting the domain holder, or
another party that is authorized to approve issuance of certificates for the
domain in question.

The contact property takes a URL as its parameter.  The following URL scheme
types SHOULD be implemented:

mailto: An SMTP email address where the domain holder or other authorized
party can be contacted.

tel: A telephone number where the domain holder or other authorized party
can be contacted.

 

Schemes other than "mailto:" or "tel:" MUST NOT be used.  Telephone numbers
MUST include the country code and be global phone numbers as defined by RFC
3966.

 

The following is an example where the holder of the domain specified the
contact property using both an email address and a phone number.

 

$ORIGIN example.com

.              CAA 0 issue "ca.example.net"

.              CAA 0 contact "mailto:domainowner at example.com"

.              CAA 0 contact "tel:+1-310-555-1212"

 

## Support for Legacy Systems

 

Some systems still do not have sufficient support for CAA records.  To allow
users of those systems to specify contact information, a legacy format using
text records is allowed.  The CAA contact property SHOULD be used instead of
TXT records, where feasible.

               

The DNS TXT record MUST be placed on the "_caa_contact" subdomain of the
domain being validated.  The DNS record MUST be named
"domain-authorization-email" or "domain-authorization-phone".  The value of
"domain-authorization-email" MUST contain a valid email address, or it
cannot be used.  The value of "domain-authorization-phone" must be a global
phone number, including country code, as defined in RFC 3966 or it cannot be
used. 

--- MOTION ENDS ---

A comparison of the changes can be found at:
https://github.com/cabforum/documents/compare/SC2-CAA-Contact?expand=1

The procedure for approval of this ballot is as follows:

Discussion (7+ days)

Start Time: 2018-07-11 10:30am EST

End Time: 2018-07-19 11:00am EST

Vote for approval (7 days)

Start Time: 2018-07-19 11:00am EST

End Time: 2018-07-26 11:00am EST

 

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