Re:Cloudflare, Mozilla, Fastly, and Apple Working on Encrypt...
by peterwwillis on Monday July 16, 2018 @08:05AM
(#17540608)
1) HPKP is dead, Chrome 67 removes support. 2) No client will flag an error if the new cert is non-EV. EV is completely useless as a security feature. 3) AFAIK no browser checks the cert transparency log.
Or when the domain uses HPKP to pin its certificate to a different CA. When the MITM CA has been added manually to the browser's root key store, most browsers allow HPKP bypass by that CA unless configured otherwise; but if the MITM is done by compromising one of the browser's default CAs, the browser won't allow a bypass.
Or if the certificate was supposed to be an EV certificate, which can only be issued by a limited number of CAs, and the compromised CA is not one of these. And even if an EV CA is compromised, AFAIK some browsers require the certificate to be in a Certificate Transparency log, and they also require that the certificate carry proof of its submission to the CT logs.