[Servercert-wg] Ballot SC14: CAA Contact Property and Associated Phone Validation Methods

Mon Jan 7 10:19:11 MST 2019

Ballot SC14: CAA Contact Property and Associated Phone Validation Methods

Purpose of Ballot: As discussed during the Validation Summit, Method 3 of
the Baseline Requirements could use some improvements to close off some
potential bad practices that might lead to security risks.  This Ballot
tightens up the rules around phone validation in order to make sure domain
authorization or control is verified with a person who is authorized to do
so by introducing a replacement for Method 3.  Validations done under Method
3 will continue to be valid until the end of the data reuse period, but new
phone based validations must use one of the new methods by the date
specified in the ballot below.

This ballot also builds on "Ballot SC13: CAA Contact Property and Associated
E-mail Validation Methods" to permit domain owners to publish Domain
Validation phone numbers in DNS CAA and DNS TXT records.  Since these phone
numbers are specifically for the purpose of validating domains, it's not
permissible to be transferred to a different number.

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

--- MOTION BEGINS ---

This ballot modifies the "Baseline Requirements for the Issuance and
Management of Publicly-Trusted Certificates" as follows, based on Version
1.6.2 with ballot SC13 changes:

Add the following two definitions to section 1.6.1:

DNS CAA Phone Contact: The phone number defined in section B.1.2.

DNS TXT Record Phone Contact: The phone number defined in section B.2.2.

In section 1.6.1, change the section references for the definition of "DNS
CAA Email Contact" from B.1.2 to B.1.1.

In section 1.6.1, change the section references for the definition of "DNS
TXT Record Email Contact" from B.2.2 to B.2.1 respectively

In section 3.2.2.4.3, after the end of the second paragraph add the
following text as a new paragraph: "CAs SHALL NOT perform validations using
this method after July 31, 2019.  Completed validations using this method
SHALL continue to be valid for subsequent issuance per the applicable
certificate data reuse periods."

Add sections 3.2.2.4.15, 3.2.2.4.16, 3.2.2.4.17 as follows:

3.2.2.4.15 Phone Contact with Domain Contact

Confirm the Applicant's control over the FQDN by calling the Domain
Contact's phone number and obtain a confirming response to validate the ADN.
Each phone call MAY confirm control of multiple ADNs provided that the same
Domain Contact phone number is listed for each ADN being verified and they
provide a confirming response for each ADN.

In the event that someone other than a Domain Contact is reached, the CA MAY
request to be transferred to the Domain Contact. 

In the event of reaching voicemail, the CA may leave the Random Value and
the ADN(s) being validated.  The Domain Contact may return the Random Number
to the CA via Phone, Email, Fax, or SMS to approve the request. 

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 Phone Contact with DNS CAA Phone Contact 

Confirm the Applicant's control over the FQDN by calling the DNS CAA Phone
Contact's phone number and obtain a confirming response to validate the ADN.
Each phone call MAY confirm control of multiple ADNs provided that the same
DNS CAA Phone Contact phone number is listed for each ADN being verified and
they provide a confirming response for each ADN.

The CA MAY NOT be transferred or request to be transferred as this phone
number has been specifically listed for the purposes of Domain Validation. 

In the event of reaching voicemail, the CA may leave the Random Value and
the ADN(s) being validated.  The DNS CAA Phone Contact may return the Random
Number to the CA via Phone, Email, Fax, or SMS to approve the request. 

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.

3.2.2.4.17 Phone Contact with DNS TXT Record Phone Contact 

Confirm the Applicant's control over the FQDN by calling the DNS TXT Record
Phone Contact's phone number and obtain a confirming response to validate
the ADN. Each phone call MAY confirm control of multiple ADNs provided that
the same DNS TXT Record Phone Contact phone number is listed for each ADN
being verified and they provide a confirming response for each ADN.

The CA MAY NOT be transferred or request to be transferred as this phone
number has been specifically listed for the purposes of Domain Validation. 

In the event of reaching voicemail, the CA may leave the Random Value and
the ADN(s) being validated.  The DNS TXT Record Contact may return the
Random Number to the CA via Phone, Email, Fax, or SMS to approve the
request.

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 sections B.1.2, B.2.2 as follows:

B.1.2. CAA contactphone Property

SYNTAX: contactemail <rfc3966 Global Number> 

The CAA contactphone property takes a phone number as its parameter.  The
entire parameter value of the MUST be a valid Global Number as defined in
RFC 3966 section 5.1.4, or it cannot be used.  Global Numbers MUST have a
preceding + and a country code and MAY contain visual separators.

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

$ORIGIN example.com.

    CAA 0 contactphone "+1 (555) 123-4567"

The contactphone property MAY be critical if the domain owner does not want
CAs who do not understand it to issue certificates for the domain.

B.2.2. DNS TXT Record Phone Contact

The DNS TXT record MUST be placed on the "_validation-contactphone"
subdomain of the domain being validated.  The entire RDATA value of this TXT
record MUST be a valid Global Number as defined in RFC 3966 section 5.1.4,
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/dougbeattie/documents/compare/master...dougbeattie:SC14--
-Phone-validation-updates 

The procedure for approval of this ballot is as follows:

Discussion (7+ days)

Start Time: 2019-01-07 12:30 Eastern

End Time: Not before 2019-01-14 12:30 Eastern

Vote for approval (7 days)

Start Time: TBD

End Time: TBD

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