I don't think we've commented on this before, but I'll note that sending an e-mail from the e-mail address listed as the contact address on a website is not one of the approved methods of showing ownership or control of a website as specified in section 3.2.2.4. The approved methods of validating ownership or control
have undergone a lot of scrutiny, and the CA/Browser Forum continues to spend lots of its time trying to make them better. Given the degree to which support and infrastructure is outsourced these days, it is tempting to say that merely comparing email addresses is a very, very bad way of confirming authenticity of requests and CAs should not rely on it. Technical measures like SPF or DMARC do not mitigate the risk that the sender is not authorized to request revocation as they do not verify that the sender owns or controls the website that they are listed as the contact address for. CAs should not accept that as proof of ownership or control, and I'm happy that we didn't. That said, the latest Baseline Requirements include Relying Parties as someone who can request revocation in section 4.9.2, in addition to "other third parties". This is basically anyone who has ever used a browser, which at this point is most of the people on the planet. I'm not sure why we don't just say "anyone can submit a Certificate Problem Report", because it's functionally equivalent (and much less confusing). We take these requests very seriously, no matter who they come from, and would encourage other CAs to do so as well. Handling revocation requests within the mandated window is often very challenging, but it's also very important to get right. The recent clarifications and improvements from Wayne's ballot do make things significantly better, but this is still an area we should pay close attention to in order to make sure we get the balance right in making sure revocations happen quickly, efficiently, and most importantly, securely when they are necessary. -Tim > -----Original Message----- > From: dev-security-policy <dev-security-policy-boun...@lists.mozilla.org> > On Behalf Of please please via dev-security-policy > Sent: Monday, December 17, 2018 5:51 PM > To: Wayne Thayer <wtha...@mozilla.com> > Cc: MDSP <dev-security-policy@lists.mozilla.org> > Subject: Re: Violation report - Comodo CA certificates revocation delays > > A lot of things changes in 3 months it seems. ?? > > The wording for the new "validation of domain authorization or control [...] > should not be relied upon" condition seems open to interpretation, so I'm > not sure if it really applies here. Wouldn't it fully cover the "no longer legally > permitted" condition as well in this case, making the latter redundant? > > In any case, I should point out that even when taking into account the latest > version of the BRs instead of the one that applied at the time (v.1.6.0), it > would still have violated the "no longer legally permitted" condition that I > previously quoted within the extended deadline of 5 days anyway. > > Thanks again Wayne for the follow-up! > > Guillaume Fortin-Debigaré > > > ________________________________ > From: Wayne Thayer <wtha...@mozilla.com> > Sent: December 17, 2018 13:00 > To: please please > Cc: MDSP > Subject: Re: Violation report - Comodo CA certificates revocation delays > > On Sun, Dec 16, 2018 at 11:49 PM please please > <pleaseiwantt...@hotmail.com<mailto:pleaseiwantt...@hotmail.com>> > wrote: > I just noticed that Comodo CA has finally posted its incident report in > https://bugzilla.mozilla.org/show_bug.cgi?id=1492006 > > Comments: > - The report suggests that no BR violation occurred because I was not the > Subscriber to fulfill the conditions in bullet point 1 of BR 4.9.1.1. However, I > believe I fulfilled the conditions for triggering the 24 hours revocation > anyway because of bullet point 6 of the same BR, which states "The CA is > made aware of any circumstance indicating that use of a Fully Qualified > Domain Name or IP address in the Certificate is no longer legally permitted > (e.g. [...] a relevant licensing or services agreement between the Domain > Name Registrant and the Applicant has terminated [...])", as I explicitly stated > in my initial revocation request email that Cloudflare was no longer > authorized to represent my domain but still controlled the private keys. > > Sectigo's (formerly Comodo's) response does seem to both admit the > violation and downplay it. Shortly after the violation the BRs were changed > to allow 5 days for most revocations, and that may be the motivation for > calling out that the Subscriber didn't request revocation. However, I believe > this case still falls under the 24-hour rule due to 4.9.1.1(4): > > The CA obtains evidence that the validation of domain authorization or > control for any Fully-Qualified Domain Name or IP address in the Certificate > should not be relied upon. > > - Comodo CA claims that my request was "potentially ambiguous", but did > not explain in what regard, nor did they ever asked me for clarifications. I > can only assume as of now that the issue was to get an exhaustive list of > certificates as I ran into the same problem and could not do so efficiently > myself, but assumed Comodo CA would have had the means necessary to > extract them easily from their own data based on my request. > > I've requested more information in the bug. This may be a case of Sectigo > falling back on the interpretation that the revocation clock doesn't start until > the certificates have been identified. However, Sectigo also accepts > responsibility by stating "The urgency of the revocation request was not > adequately communicated as the request was passed along." > > - I'm concerned that the incident report was posted more than 2 months past > Mozilla's soft deadline to do so, especially when considering that the incident > was also about being late to take necessary action for a deadline. > > Yes, this is a concern. When a CA exhibits a pattern of slow responses, it is > taken into consideration when Mozilla is making decisions about the CA, such > as whether to include new roots. > > Let me know if you need additional information from me to complete your > assessment of the incident. > > Guillaume Fortin-Debigaré > ________________________________ > From: please please > <pleaseiwantt...@hotmail.com<mailto:pleaseiwantt...@hotmail.com>> > Sent: October 11, 2018 19:19 > To: Wayne Thayer > Cc: MDSP > Subject: Re: Violation report - Comodo CA certificates revocation delays > > I was under the impression that CAs were allowed to remove CRL entries and > OCSP support for expired certificates for some reason. Good to know! > > On a slightly-unrelated note, you might also want to poke Comodo CA about > https://bugzilla.mozilla.org/show_bug.cgi?id=1461391 > > Thanks again! > > Guillaume Fortin-Debigaré > ________________________________ > From: Wayne Thayer > <wtha...@mozilla.com<mailto:wtha...@mozilla.com>> > Sent: October 11, 2018 13:53 > To: > pleaseiwantt...@hotmail.com<mailto:pleaseiwantt...@hotmail.com> > Cc: MDSP > Subject: Re: Violation report - Comodo CA certificates revocation delays > > I just poked Comodo in the bug - > https://bugzilla.mozilla.org/show_bug.cgi?id=1492006 > > CT Logs are designed such that certificates cannot be removed from them. > The evidence will not disappear once the certificates expire. > > On Wed, Oct 10, 2018 at 5:26 PM please please > <pleaseiwantt...@hotmail.com<mailto:pleaseiwantt...@hotmail.com>> > wrote: > Any update behind the scenes about this issue? I've noticed that the soft limit > to fill an Incident Report expired more than a week ago, and I'm starting to > be a bit worried that some of the evidence in the CT logs might disappear if > the investigation is not completed before December 6th, the earliest > expiration date among the affected certificates. > > Guillaume Fortin-Debigaré > ________________________________ > From: please please > <pleaseiwantt...@hotmail.com<mailto:pleaseiwantt...@hotmail.com>> > Sent: September 17, 2018 23:39 > To: Wayne Thayer > Cc: MDSP > Subject: Re: Violation report - Comodo CA certificates revocation delays > > Good to know, and thank you very much for following up on this! > > Small update by the way: I finally received a reply from Comodo CA > confirming their 2nd wave of revocations a few hours ago, on September 17 > at 16:55 UTC to be exact. Strangely, it was in response to an email where I > informed them that I had already noticed they fully completed my revocation > request. I don't think it's a relevant detail but I wanted to mention it to avoid > any potential confusion. > > Guillaume Fortin-Debigaré > > ________________________________ > From: Wayne Thayer > <wtha...@mozilla.com<mailto:wtha...@mozilla.com>> > Sent: September 17, 2018 20:09 > To: > pleaseiwantt...@hotmail.com<mailto:pleaseiwantt...@hotmail.com> > Cc: MDSP > Subject: Re: Violation report - Comodo CA certificates revocation delays > > I have created a bug and requested a response from Comodo: > https://bugzilla.mozilla.org/show_bug.cgi?id=1492006 > > As noted, there are no specific requirements regarding how CAs validate > revocation requests in the BRs. Every CA may do this however they choose, > so I don't believe there is any action required in regard to DigiCert's response > to their problem report. > > - Wayne > > On Sun, Sep 16, 2018 at 8:30 PM please please via dev-security-policy <dev- > security-pol...@lists.mozilla.org<mailto:dev-security- > pol...@lists.mozilla.org>> wrote: > Hello, I am the domain owner of debigare.com<http://debigare.com>. I > would like to make you aware that Comodo CA took more than 5 days to > revoke certificates they had signed for my domain and subdomains after > requesting them to do through their sslabuse email address, past the 24 > hours maximum mentioned in the Baseline Requirements as stipulated in > section 4.9.1.1. > > For context, I was previously using Cloudflare's Universal SSL feature, but > disabling it did not revoke the old certificates that had not yet expired, but > simply removed them from its system, and some of the certificates were still > valid for more than 6 months. > > I first attempted to contact Cloudflare's support to ask them to revoke the > certificates themselves on September 6 at 7:43 UTC. This only led to > irrelevant responses and confused customer support agents that had no idea > what I was talking about, and this appeared to go nowhere. I eventually got > a response from them on September 11 at 5:53 UTC that they would request > CAs to perform the revocation, but that was after I did so myself, and I never > got a status report back afterwards. > > There were two CAs affected by this issue. The vast majority of certificates > were signed by Comodo CA, and the rest by DigiCert. I did not run into any > issues with DigiCert (they in fact proactively checked with Cloudflare my > claim and revoked the certificates before I even had the chance to attempt > their domain ownership challenge), but Comodo CA was another story > entirely. > > My first request to Comodo CA to revoke the certificates for > debigare.com<http://debigare.com> and all of its subdomains was on > September 8 at 4:37 UTC. I did not get a reply until September 9 at 15:53 UTC > stating that the certificates have been revoked. Not only was this past the 24 > hours requirement, but it was also false, as only the most recent certificates > had been revoked, not all of them. I mentioned to them their mistake on > September 10 at 5:55 UTC with a full list of affected certificates just in case > my initial request was unclear to them, and never got a reply back. I did, > however, notice that the certificates eventually got revoked on September > 13 at 16:04 UTC according to their Certificate Transparency logs, a fact that I > only discovered on September 15. Assuming the log is correct, that would be > a delay of more than 3 days after notifying them of the incomplete > revocation, more than 5 days after my initial request to them, and more than > a week until I finally noticed the problem was fixed. It's also worth noting > that throughout this entire series of events, Comodo CA never requested > proof of domain ownership beyond the evidence I initially provided, so that > cannot explain the delays. > > One detail that I'm not sure about is why my initial evidence for domain > ownership was apparently sufficient for Comodo CA but not for DigiCert. On > this regard, the only evidence I provided to both of them was that the email > address I used to contact them matched the contact information on my > website. (My emails were protected with SPF, DKIM and DMARC for > authenticity.) For some reason, DigiCert believed that this evidence did not > met the Baseline Requirements for my request, a claim that I am currently > unable to verify as I cannot find anything of the sort in them. > > You can read the full story on my blog, which I hope will be sufficient to > prove my identity: https://www.debigare.com/4-unexpected-issues-i- > encountered-upon-switching-web-hosts/ > > I can also provide a full copy of the email exchange I had with Comodo CA as > evidence on request. > > Guillaume Fortin-Debigaré > _______________________________________________ > dev-security-policy mailing list > dev-security-policy@lists.mozilla.org<mailto:dev-security- > pol...@lists.mozilla.org> > https://lists.mozilla.org/listinfo/dev-security-policy > _______________________________________________ > dev-security-policy mailing list > dev-security-policy@lists.mozilla.org > https://lists.mozilla.org/listinfo/dev-security-policy
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