<div dir="ltr"><br><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Apr 7, 2017 at 10:23 AM, Ryan Sleevi via Public <span dir="ltr"><<a href="mailto:public@cabforum.org" target="_blank">public@cabforum.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">That's just a press summary of what Bruce linked.<div><br></div><div>It sounds like folks don't understand Ivan's criticisms or the problems with HPKP. Since this list is primarily targetted towards CAs, I encourage you to reach out to Ivan (or if he still lurks) about how CAs could make HPKP more viable, if they're interested. I've already described how CAs are uniquely qualified to provide that assistance. It's the lack of that assistance that has created the significant risks. That's not something Gerv or Jody and I can solve - that's on CAs.</div><div><br></div><div>This is no different than, for example, CAs needing to disclose what CAA domains they accept, as otherwise, CAA cannot be (effectively) used.</div></div></blockquote><div><br></div><div>To try and sum up what I think Ryan is saying, CAs could use HPKP to achieve the same effect as an "EV-Only" pin if CAs each publicly published and maintained the hash of their public keys that correspond to EV-only issuing CAs, for customers to rely on.</div><div><br></div><div>Then a customer who doesn't wish to pin to a small set of CAs or end entity certs, out of fear of bricking themselves, could construct an "EV-only" set of pins that encompassed all publicly trusted EV-issuing CAs. The technical risks would be similar than a hypothetical "EV-only" pinning standard, and require no further effort on the part of browsers. </div><div><br></div><div>The primary issue for server operators is that that server operators would need to keep their pins up to date as the set of EV-only issuing CAs change, but I would think that that rate of change might be manageable, and even a fairly out-of-date set of pins would still leave ample breathing room to migrate CAs if an issue occurs.</div><div><br></div><div>The primary issue for CAs is that you'd really want to coordinate to put these in one place, and maintain an authoritative "EV-only" set of pins for server operators to refer to. It wouldn't be reasonable to ask interested server operators to hunt it all down and construct the pins themselves, and wouldn't be effective -- people would make mistakes and then blame the CAs.</div><div><br></div><div>This is the sort of thing I'd think that CAs and groups invested in EV, such as the CA Security Council, might promote. If the market is actually interested in the concept of "EV-only" pinning, this would be a great way to demonstrate it.</div><div><br></div><div>-- Eric</div><div><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="HOEnZb"><div class="h5"><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Apr 7, 2017 at 10:21 AM, Christian Heutger <span dir="ltr"><<a href="mailto:ch@psw.net" target="_blank">ch@psw.net</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:Calibri">HPKP is vulnerable, look at
<a href="https://www.heise.de/security/artikel/Wachsende-Kritik-an-Public-Key-Pinning-fuer-HTTPS-3324703.html" target="_blank">
https://www.heise.de/security/<wbr>artikel/Wachsende-Kritik-an-Pu<wbr>blic-Key-Pinning-fuer-HTTPS-33<wbr>24703.html</a> (you may use Google Translator) from second headline<u></u><u></u></span></p>
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<p class="MsoNormal"><b><span style="font-family:Calibri;color:black">Von: </span>
</b><span style="font-family:Calibri;color:black">Public <<a href="mailto:public-bounces@cabforum.org" target="_blank">public-bounces@cabforum.org</a>> im Auftrag von Ryan Sleevi via Public <<a href="mailto:public@cabforum.org" target="_blank">public@cabforum.org</a>><br>
<b>Antworten an: </b>CA/Browser Forum Public Discussion List <<a href="mailto:public@cabforum.org" target="_blank">public@cabforum.org</a>><br>
<b>Datum: </b>Freitag, 7. April 2017 um 16:16<br>
<b>An: </b>Bruce Morton <<a href="mailto:Bruce.Morton@entrustdatacard.com" target="_blank">Bruce.Morton@entrustdatacard.<wbr>com</a>><br>
<b>Cc: </b>Ryan Sleevi <<a href="mailto:sleevi@google.com" target="_blank">sleevi@google.com</a>>, CA/Browser Forum Public Discussion List <<a href="mailto:public@cabforum.org" target="_blank">public@cabforum.org</a>><br>
<b>Betreff: </b>Re: [cabfpub] [EXTERNAL] Brazilian bank DNS heist<u></u><u></u></span></p>
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<p class="MsoNormal">On Fri, Apr 7, 2017 at 9:27 AM, Bruce Morton <<a href="mailto:Bruce.Morton@entrustdatacard.com" target="_blank">Bruce.Morton@entrustdatacard.<wbr>com</a>> wrote:<u></u><u></u></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:Calibri;color:#1f497d">Sorry I missed that, but isn’t pinning high risk? I don’t think that any CA would recommend pinning
as it is unsupportable; we can’t do anything when it fails. I think Subscribers should review pinning before deploying,
<a href="https://blog.qualys.com/ssllabs/2016/09/06/is-http-public-key-pinning-dead" target="_blank">
https://blog.qualys.com/ssllab<wbr>s/2016/09/06/is-http-public-<wbr>key-pinning-dead</a>.</span><span lang="EN-US"><u></u><u></u></span></p>
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<p class="MsoNormal">For what it's worth, many of the complaints in that blog relate to CAs lack of disclosure related to their infrastructure - that's what creates the risks. So if CAs were more technically savvy, and worked to help understand their customers
needs, it's very much viable.<u></u><u></u></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:Calibri;color:#1f497d">I think the value of EV is that those certificates are not issued to attackers. So it would be great
if a Subscriber could state that their site only uses EV and that the browser respected that statement.</span><span lang="EN-US"><u></u><u></u></span></p>
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<p class="MsoNormal">And customers have that capability - if CAs, particularly their CA, is technically capable and/or transparent. The browser manufacturers have already give you that capability, if you chose to use it.<u></u><u></u></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:Calibri;color:#1f497d">I also think that this statement might be better to be put in the HSTS header. HSTS is low risk, EV
is highly available and stating EV-only would be applicable to most CAs. This allows the Subscriber to move from one CA to another without bricking their site by pinning to a root or intermediate.</span><span lang="EN-US"><u></u><u></u></span></p>
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<p class="MsoNormal">I disagree, and was pointing out how you can already accomplish this without requiring new features that accomplish the same as existing features =)<u></u><u></u></p>
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