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</o:shapelayout></xml><![endif]--></head><body lang=EN-GB link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Hi Jeremy, all,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> My proposed amendment has two parts.<o:p></o:p></span></p><p class=MsoListParagraphCxSpFirst style='text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><span style='mso-list:Ignore'>1)<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>An alternative to using a ‘Random Value’ for the practical demonstrations of control.<o:p></o:p></span></p><p class=MsoListParagraphCxSpLast style='text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><span style='mso-list:Ignore'>2)<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Specifying the use of a ‘Random Value’ for (at least) the email methods.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>1) Using a ‘Random Value’ in sub-sections 6, 7, and 10 is a good way to ensure that the practical demonstration of control is related to this particular certificate request. I don’t propose removing that as an option because it is a good idea. <br>We think, however, that Comodo’s current technique is superior to the Random Value for sections 6, 7, and 10 and would like to see it permitted as an alternative. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>We generate a token from the CSR and we have the applicant put that token in place in a file (6) or in a DNS record (7) or to be returned as part of a TLS response (10).<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>The token must strongly be cryptographically related to the subscribers public key, and we use a concatenation of the output of two different hash algorithms to ensure that is the case. I’m sure there are other ways to generate the tokens which are also perfectly adequate.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>The advantage of our technique in using a token derived from the subscriber’s key instead of a Random Value is that any change in the key to be included in the certificate during the certificate application process implicitly requires that the demonstration of practical control be repeated. <br>That follows because if the key to be certified is changed the token will change and the CA would be required to verify the token before issuance (for 6, 7, and 10).<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Why should we consider the repetition of a practical demonstration of control upon a subscriber key change to be beneficial?<br>During the certificate application process a CA may allow the subscriber to provide a changed key (new CSR). <br>While a diligent CA may already require that an application be restarted from scratch when a new key is provided, it is not crystal clear in the BRs that that must be the case. A less diligent CA might leave itself open to a spoofed inbound email, perhaps combined with a social engineering phonecall, to have the CA accept a replacement key from the attacker masquerading as the applicant. Such an attack, if successful, could cause the CA to issue a certificate for the genuine applicant’s domain but using the attacker’s public key. That gives the attacker a window of opportunity to MITM or otherwise impersonate the applicant until the error is discovered (which it is likely to be since the issued certificate will not ‘work’ for the genuine applicant) and revoked (which may or may not happen if the cause of the certificate’s not ‘working’ for the subscriber is wrongly attributed to subscriber error instead of attack).<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>2) The methods described in sub-sections 2 and 4 are the common means by which authorization for issuance may be confirmed by email. Since these are both simple email challenge/response methods we feel that the use of a ‘Random Value’ should also be required in these sub-sections. <br>We’d also like to see it required for any of the confirmation relying on a Reliable Method of Communication, but we can see that reading out 128 bits of entropy over the phone may be burdensome.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I’ve attempted to include Gerv’s changes too. The Base Domain doesn’t completely cover the wording in the note at the end, since that deals with different behaviour for CCtlds.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Should we have a visible place-holder for the now absent sub-section 3?<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Regards<br>Robin Alden<br>Comodo<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div style='border:none;border-left:solid blue 1.5pt;padding:0cm 0cm 0cm 4.0pt'><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal style='margin-bottom:0cm;margin-bottom:.0001pt'><b><span lang=EN-US style='font-family:"Tahoma","sans-serif";color:windowtext'>From:</span></b><span lang=EN-US style='font-family:"Tahoma","sans-serif";color:windowtext'> public-bounces@cabforum.org [mailto:public-bounces@cabforum.org] <b>On Behalf Of </b>Jeremy Rowley<br><b>Sent:</b> 15 April 2015 19:29<br><b>To:</b> public@cabforum.org<br><b>Subject:</b> [cabfpub] Domain validation<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal style='margin-bottom:12.0pt'><span lang=EN-US style='font-size:11.0pt;font-family:"Times New Roman","serif";color:windowtext'>With removal of the opinion letters, I think this is ready for a ballot. Are there two endorsers?<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Times New Roman","serif";color:windowtext'>Amendment to Section 11.1.1 of CA/Browser Forum Baseline Requirements to clarify acceptable methods of validating domain control:<o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-18.0pt'><span lang=EN-US style='font-size:11.0pt;font-family:"Times New Roman","serif";color:windowtext'>1)</span><span lang=EN-US style='font-size:7.0pt;font-family:"Times New Roman","serif";color:windowtext'> </span><span lang=EN-US style='font-size:11.0pt;font-family:"Times New Roman","serif";color:windowtext'>Add the following definitions: <o:p></o:p></span></p><p class=MsoPlainText><span lang=EN-US style='font-family:"Times New Roman","serif"'>Base Domain: 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. “domain.co.uk” or “domain.com”).<o:p></o:p></span></p><p class=MsoPlainText><span lang=EN-US style='font-family:"Times New Roman","serif"'><o:p> </o:p></span></p><p class=MsoPlainText><span lang=EN-US style='font-family:"Times New Roman","serif"'>Random Value: A value specified by a CA to the Applicant that exhibits 128 bits of entropy.<o:p></o:p></span></p><p class=MsoPlainText><span lang=EN-US style='font-family:"Times New Roman","serif"'><o:p> </o:p></span></p><p class=MsoListParagraph style='text-indent:-18.0pt'><span lang=EN-US style='font-size:11.0pt;font-family:"Times New Roman","serif";color:windowtext'>2)</span><span lang=EN-US style='font-size:7.0pt;font-family:"Times New Roman","serif";color:windowtext'> </span><span lang=EN-US style='font-size:11.0pt;font-family:"Times New Roman","serif";color:windowtext'>Section 11.1.1 of the CA/Browser Forum’s Baseline Requirements is amended as follows:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Times New Roman","serif";color:windowtext'>…<o:p></o:p></span></p><p class=MsoListParagraph style='mso-margin-top-alt:12.0pt;margin-right:0cm;margin-bottom:6.0pt;margin-left:54.0pt;mso-add-space:auto;text-align:justify;text-indent:-36.0pt;page-break-after:avoid'><b><i><span lang=EN-US style='font-size:11.0pt;font-family:"Times New Roman","serif";color:windowtext'>11.1.1</span></i></b><b><i><span lang=EN-US style='font-size:7.0pt;font-family:"Times New Roman","serif";color:windowtext'> </span></i></b><b><i><span lang=EN-US style='font-size:11.0pt;font-family:"Times New Roman","serif";color:windowtext'>Authorization by Domain Name Registrant<o:p></o:p></span></i></b></p><p class=MsoNormal style='margin-bottom:6.0pt;text-align:justify'><span lang=EN-US style='font-size:11.0pt;font-family:"Times New Roman","serif";color:windowtext'>For each Fully-Qualified Domain Name listed in a Certificate, the CA SHALL confirm that, as of the date the Certificate was issued, the Applicant either is the Domain Name Registrant or has control over the FQDN by: <o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:6.0pt;margin-left:36.0pt;text-align:justify;text-indent:-18.0pt'><span lang=EN-US style='font-size:11.0pt;font-family:"Times New Roman","serif";color:windowtext'>1. Confirming the Applicant as the Domain Name Registrant directly with the Domain Name Registrar through a Reliable Method of Communication, for example using information provided through WHOIS; or<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:6.0pt;margin-left:36.0pt;text-align:justify;text-indent:-18.0pt'><span lang=EN-US style='font-size:11.0pt;font-family:"Times New Roman","serif";color:windowtext'>2. Confirming authorization of the Certificate’s issuance directly with the Domain Name Registrant using a Reliable Method of Communication that is (i) obtained from the Domain Name Registrar or (ii) listed as the “registrant”, “technical”, or “administrative” contact for the WHOIS record of the Base Domain; or <o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:6.0pt;margin-left:36.0pt;text-align:justify;text-indent:-18.0pt'><span lang=EN-US style='font-size:11.0pt;font-family:"Times New Roman","serif";color:windowtext'>4. Confirming authorization for the Certificate’s issuance through an email address created by pre-pending ‘admin’, ‘administrator’, ‘webmaster’, ‘hostmaster’, or ‘postmaster’ in the local part, followed by the at-sign (“@”), followed by the Domain Name, which may be formed by pruning zero or more components from the requested FQDN; or<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:6.0pt;margin-left:36.0pt;text-align:justify;text-indent:-18.0pt'><span lang=EN-US style='font-size:11.0pt;font-family:"Times New Roman","serif";color:windowtext'>5. Relying upon a Domain Authorization Document that meets the requirements listed below; or<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:6.0pt;margin-left:36.0pt;text-align:justify;text-indent:-18.0pt'><span lang=EN-US style='font-size:11.0pt;font-family:"Times New Roman","serif";color:windowtext'>6. Having the Applicant demonstrate control over the FQDN or Base Domain by adding a file containing a Random Value to the “/.well-known/certificate” directory at either the FQDN or the Base Domain in accordance with RFC 5785; or<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:6.0pt;margin-left:36.0pt;text-align:justify;text-indent:-18.0pt'><span lang=EN-US style='font-size:11.0pt;font-family:"Times New Roman","serif";color:windowtext'>7. Having the Applicant demonstrate control over the FQDN or Base Domain by the Applicant making a change to information in a DNS record for the FQDN or Base Domain where the change is a Random Value; or<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:6.0pt;margin-left:36.0pt;text-align:justify;text-indent:-18.0pt'><span lang=EN-US style='font-size:11.0pt;font-family:"Times New Roman","serif";color:windowtext'>8. Having the Applicant demonstrate control over the requested FQDN by the CA confirming, in accordance with section 11.1.1, the Applicant’s controls the FQDN (or Base Domain of the FQDN) returned from a DNS lookup for CNAME records for the requested FQDN; or<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:6.0pt;margin-left:36.0pt;text-align:justify;text-indent:-18.0pt'><span lang=EN-US style='font-size:11.0pt;font-family:"Times New Roman","serif";color:windowtext'>9. Having the Applicant demonstrate control over the requested FQDN by the CA confirming, in accordance with section 11.1.2, that the Applicant controls an IP address returned from a DNS lookup for A or AAAA records for the requested FQDN; or<o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:6.0pt;margin-left:36.0pt;text-align:justify;text-indent:-18.0pt'><span lang=EN-US style='font-size:11.0pt;font-family:"Times New Roman","serif";color:windowtext'>10. Having the Applicant demonstrate control over the FQDN by providing a TLS service on a host found in DNS for the FQDN and having the CA (i) initiate a TLS connection with the host and (ii) verify a Random Value that is a in a format recognized as a valid TLS response.<o:p></o:p></span></p><p class=MsoNormal style='margin-bottom:10.0pt'><span lang=EN-US style='font-size:11.0pt;font-family:"Times New Roman","serif";color:windowtext'><o:p> </o:p></span></p><p class=MsoNormal style='margin-bottom:10.0pt'><span lang=EN-US style='font-size:11.0pt;font-family:"Times New Roman","serif";color:windowtext'>Note: For purposes of determining the appropriate domain name level or Domain Namespace, the registerable Domain Name is the second-level domain for generic top-level domains (gTLD) such as .com, .net, or .org, or, if the Fully Qualified Domain Name contains a 2 letter Country Code Top-Level Domain (ccTLD), then the domain level is whatever is allowed for registration according to the rules of that ccTLD. If the CA relies upon a Domain Authorization Document to confirm the Applicant’s control over a FQDN, then the Domain Authorization Document MUST substantiate that the communication came from either the Domain Name Registrant (including any private, anonymous, or proxy registration service) or the Domain Name Registrar listed in the WHOIS. The CA MUST verify that the Domain Authorization Document was either (i) dated on or after the certificate request date or (ii) used by the CA to verify a previously issued certificate and that the Domain Name’s WHOIS record has not been modified since the previous certificate’s issuance.<o:p></o:p></span></p><p class=MsoNormal style='margin-bottom:10.0pt'><span lang=EN-US style='font-size:11.0pt;font-family:"Times New Roman","serif";color:windowtext'>Note: FQDNs may be listed in Subscriber Certificates using dNSNames in the subjectAltName extension or in Subordinate CA Certificates via dNSNames in permittedSubtrees within the Name Constraints extension.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Times New Roman","serif";color:windowtext'>Note: For the purpose of verifying a wildcard FQDN, the CA MUST verify either the Base Domain of the wildcard FQDN or the entire Domain Name Label to the right of the wildcard character. <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Times New Roman","serif";color:windowtext'><o:p> </o:p></span></p><p class=line874><span lang=EN-US style='font-size:11.0pt;color:windowtext'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Times New Roman","serif";color:windowtext'><o:p> </o:p></span></p></div></div></body></html>