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Those hundreds of trusted root certificates are, at least to some extent, held to operational and security standards. If your ISP used one of those certificates

by ryan-c 11y ago

Those hundreds of trusted root certificates are, at least to some extent, held to operational and security standards. If your ISP used one of those certificates to MitM your traffic, there is a very real possibility of that certificate being blacklisted by browsers. Further, unlike the Kazakhstan certificate, those root certificates cannot bypass HTTPS public key pinning (HPKP).

chatmasta 11y ago
Thanks for the info! I didn't know some of this. Two questions: 1: > there is a very real possibility of that certificate being blacklisted by browsers Why would a browser blacklist a certificate? Is it possible for a browser to detect a MITM attack when the SSL traffic is all signed by the private key of a trusted root certificate? 2: > Further, unlike the Kazakhstan certificate, those root certificates cannot bypass HTTPS public key pinning (HPKP). You are saying that pre-installed root certificates behave differently than user-installed root certificates? Wouldn't that behavior be system-dependent? I was under the impression that no root certificates can bypass public key pinning... isn't that sort of the point of pinning? That it allows traffic encryption outside of the normal trust hierarchy? What makes the Kazakhstan cert special that allows it to break pinning?
- ryan-c 11y ago
  1: A server using HPKP with the reporting feature turned on will receive reports from browsers when the certificate does not match what was expected (provided HPKP is being honored). 2: Browsers ignore HPKP when the server certificate is trusted through a user or administrator installed root CA. All mainstream browsers on all platforms behave in this way. This is by design specifically to allow enterprises to do the sort of traffic interception that Kazakhstan is implementing. The rationale is that if an attacker is able to get as far as installing their own CA on your system, you're screwed anyway.

by ryan-c 11y ago

chatmasta 11y ago

Thanks for the info! I didn't know some of this. Two questions: 1: > there is a very real possibility of that certificate being blacklisted by browsers Why would a browser blacklist a certificate? Is it possible for a browser to detect a MITM attack when the SSL traffic is all signed by the private key of a trusted root certificate? 2: > Further, unlike the Kazakhstan certificate, those root certificates cannot bypass HTTPS public key pinning (HPKP). You are saying that pre-installed root certificates behave differently than user-installed root certificates? Wouldn't that behavior be system-dependent? I was under the impression that no root certificates can bypass public key pinning... isn't that sort of the point of pinning? That it allows traffic encryption outside of the normal trust hierarchy? What makes the Kazakhstan cert special that allows it to break pinning?

ryan-c 11y ago
1: A server using HPKP with the reporting feature turned on will receive reports from browsers when the certificate does not match what was expected (provided HPKP is being honored). 2: Browsers ignore HPKP when the server certificate is trusted through a user or administrator installed root CA. All mainstream browsers on all platforms behave in this way. This is by design specifically to allow enterprises to do the sort of traffic interception that Kazakhstan is implementing. The rationale is that if an attacker is able to get as far as installing their own CA on your system, you're screwed anyway.