[cabfpub] [Servercert-wg] Ballot SC4 - email and CAA CONTACT

Corey Bonnell CBonnell at trustwave.com
Fri Aug 3 09:04:13 MST 2018


Hi Tim,
Can you provide an example of how a TXT record would be formatted to convey the email address (as was done for the CAA records)? It’s not clear to me based on the description given.

Thanks,

Corey Bonnell
Senior Software Engineer

Trustwave | SMART SECURITY ON DEMAND
https://www.trustwave.com<http://www.trustwave.com/>

From: Servercert-wg <servercert-wg-bounces at cabforum.org> on behalf of Tim Hollebeek via Servercert-wg <servercert-wg at cabforum.org>
Reply-To: Tim Hollebeek <tim.hollebeek at digicert.com>, CA/B Forum Server Certificate WG Public Discussion List <servercert-wg at cabforum.org>
Date: Friday, August 3, 2018 at 11:50 AM
To: CA/Browser Forum Public Discussion List <public at cabforum.org>, "servercert-wg at cabforum.org" <servercert-wg at cabforum.org>
Subject: [Servercert-wg] Ballot SC4 - email and CAA CONTACT


Ballot SC4: CAA Contact Property and Associated E-mail 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 1.6.0:
Add Section 3.2.2.4.13: Domain Owner Email in CAA
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 of the Authorization Domain Name 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 ADN being validated.

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 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 of the Authorization Domain Name in the format 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 ADN being validated.
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 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 type SHOULD be implemented:
mailto: An SMTP email address where the domain holder or other authorized party can be contacted.

Schemes other than "mailto:" MUST NOT be used.

The following is an example where the holder of the domain specified the contact property using an email address.

$ORIGIN example.com<http://scanmail.trustwave.com/?c=4062&d=rfnk28lbSPhWC4h7ghzRbUm0O2r_iB1ji9mEi2rn9g&s=5&u=http%3a%2f%2fexample%2ecom>
.              CAA 0 issue “ca.example.net”
.              CAA 0 contact “mailto:domainowner at example.com”

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 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".  The value of "domain-authorization-email" MUST contain a valid email address, or it cannot be used.

--- MOTION ENDS ---
*** WARNING ***: USE AT YOUR OWN RISK.  THE REDLINE BELOW IS NOT THE OFFICIAL VERSION OF THE CHANGES (CABF Bylaws, Section 2.4(a)):

A comparison of the changes can be found at: https://github.com/cabforum/documents/compare/Ballot-SC4---CAA-CONTACT-email?diff=unified&expand=1<https://scanmail.trustwave.com/?c=4062&d=rfnk28lbSPhWC4h7ghzRbUm0O2r_iB1ji4qIgT_i8A&s=5&u=https%3a%2f%2fgithub%2ecom%2fcabforum%2fdocuments%2fcompare%2fBallot-SC4---CAA-CONTACT-email%3fdiff%3dunified%26amp%3bexpand%3d1>
The procedure for approval of this ballot is as follows:
Discussion (7+ days)
Start Time: 2018-08-03 11:50 Eastern
End Time: Not before 2018-08-10 11:50 Eastern
Vote for approval (7 days)
Start Time: TBD
End Time: TBD
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