<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=utf-8"><meta name=Generator content="Microsoft Word 15 (filtered medium)"><style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman",serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
p.msonormal0, li.msonormal0, div.msonormal0
{mso-style-name:msonormal;
mso-margin-top-alt:auto;
margin-right:0in;
mso-margin-bottom-alt:auto;
margin-left:0in;
font-size:12.0pt;
font-family:"Times New Roman",serif;}
span.EmailStyle18
{mso-style-type:personal-reply;
font-family:"Calibri",sans-serif;
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;
font-family:"Calibri",sans-serif;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>We are talking about the same thing (wildcard DNS records). <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>Examples:<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>sleevi.example.com CNAME vdomain.com<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>*.example.com CNAME vdomain.com<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><rnd>.example.com CNAME vdomain.com<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>The BRs permit verification of each of these by establishing control over vdomain.com (under the definition of authorization domain name). <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>If *.example.com can be verified this way, what is different between verifying *.example.com and <rnd>.example.com to verify all sub domains of example.com? All the RND does is make it so the website doesn’t have to point to vdomain.com.<o:p></o:p></span></p><p class=MsoNormal><a name="_MailEndCompose"><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p> </o:p></span></a></p><p class=MsoNormal><span style='mso-bookmark:_MailEndCompose'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>Jeremy<o:p></o:p></span></span></p><p class=MsoNormal><span style='mso-bookmark:_MailEndCompose'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><o:p> </o:p></span></span></p><span style='mso-bookmark:_MailEndCompose'></span><p class=MsoNormal><b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>From:</span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> public-bounces@cabforum.org [mailto:public-bounces@cabforum.org] <b>On Behalf Of </b>Ryan Sleevi<br><b>Sent:</b> Friday, September 2, 2016 4:05 PM<br><b>To:</b> Jeremy Rowley <jeremy.rowley@digicert.com><br><b>Cc:</b> public@cabforum.org<br><b>Subject:</b> Re: [cabfpub] CNAME-based validation<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>Jeremy,<o:p></o:p></p><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Perhaps it wasn't clear, I wasn't speaking of wildcard certificates, but wildcard DNS rules, in which all requests for a given subdomain return a preconfigured record type. While for TXT and CAA records this is quite uncommon, it's exceedingly common to have CNAME records.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>That is, both <rnd>.<a href="http://example.com">example.com</a> and <a href="http://sleevi.example.com">sleevi.example.com</a> may both CNAME to <a href="http://example.com">example.com</a>, by virtue of of the host putting a rule of "*.<a href="http://example.com">example.com</a> 3600 CNAME <a href="http://example.com">example.com</a>"<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>I am attempting to assert that placing the <rnd> in the subdomain is insufficient proof of authorization, and is meaningfully and tangibly different than the proof of control demonstrated in 3.2.2.4.7.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>As I read your wording, it suggests the following:<o:p></o:p></p></div><div><p class=MsoNormal>CA looks up <rnd>.<a href="http://example.com">example.com</a><o:p></o:p></p></div><div><p class=MsoNormal><rnd>.<a href="http://example.com">example.com</a> points to <a href="http://example.com">example.com</a><o:p></o:p></p></div><div><p class=MsoNormal>CA sees it previously issued a certificate for <a href="http://example.com">example.com</a> using one of the other methods<o:p></o:p></p></div><div><p class=MsoNormal>CA issues certificate for <rnd>.<a href="http://example.com">example.com</a><o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>That concerns me.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Peter's rewording suggests the inverse:<o:p></o:p></p></div><div><p class=MsoNormal>CA looks up _<a href="http://certvalidation.example.com">certvalidation.example.com</a><o:p></o:p></p></div><div><p class=MsoNormal>_<a href="http://certvalidation.example.com">certvalidation.example.com</a> points (CNAMEs) to <rnd>.validation.[nameofca].com<o:p></o:p></p></div><div><p class=MsoNormal>CA issues certificate for <a href="http://example.com">example.com</a><o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>This is much less concerning.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Could you help clarify which you intend, and for what names/purposes?<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>On Fri, Sep 2, 2016 at 2:52 PM, Jeremy Rowley <<a href="mailto:jeremy.rowley@digicert.com" target="_blank">jeremy.rowley@digicert.com</a>> wrote:<o:p></o:p></p><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt'><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>Wildcard domains are already allowed. We can verify Wildcard DNS because a CNAME for *.</span><a href="http://domain.com" target="_blank"><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>domain.com</span></a><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> is pointing to a record previously verified. This verification method is permitted under the definition of Authorization Domain Name (where the FQDN returned by a CNAME lookup can be used to verify the requested FQDN). Although <rnd>.</span><a href="http://domain.com" target="_blank"><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>domain.com</span></a><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> isn’t necessarily distinguishable from *.</span><a href="http://domain.com" target="_blank"><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>domain.com</span></a><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>, the validation ends up being the same because either its considered an Authorized Domain Name (under the definition) or it was validated as a random value in this new method. </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>For example:</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>*.</span><a href="http://domain.com" target="_blank"><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>domain.com</span></a><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> -> </span><a href="http://dcv.example.com" target="_blank"><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>dcv.example.com</span></a><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> (validated under the Authorized Domain Name section)</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><rnd>.</span><a href="http://domain.com" target="_blank"><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>domain.com</span></a><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> -></span><a href="http://validation.example.com" target="_blank"><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>validation.example.com</span></a><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> (validated under this new section)</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><a name="m_-6404224304106461886__MailEndCompose"><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> </span></a><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>Because each is validated properly, tracking which exact section was used in the validation isn’t necessary.</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>Jeremy</span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>From:</span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> Ryan Sleevi [mailto:</span><a href="mailto:sleevi@google.com" target="_blank"><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>sleevi@google.com</span></a><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>] <br><b>Sent:</b> Friday, September 2, 2016 3:28 PM<br><b>To:</b> Jeremy Rowley <</span><a href="mailto:jeremy.rowley@digicert.com" target="_blank"><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>jeremy.rowley@digicert.com</span></a><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>><br><b>Cc:</b> </span><a href="mailto:public@cabforum.org" target="_blank"><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>public@cabforum.org</span></a><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'><br><b>Subject:</b> Re: [cabfpub] CNAME-based validation</span><o:p></o:p></p><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><o:p> </o:p></p></div></div></div></div></div></blockquote></div></div></div></div></div></body></html>