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A comment on Cloudflare, Mozilla, Fastly, and Apple Working on Encrypted SNI. Parent comment

Re:Cloudflare, Mozilla, Fastly, and Apple Working on Encrypt... by tialaramex on Monday July 16, 2018 @04:39AM (#17539667)
The intent is that you'd be using a secured DNS channel such as DoH or DoT to obtain your DNS results - so an adversary can't rewrite the DNS records.

This proposal supposes that when we've decided to talk to example.com we may as well ask a DNS query that requests not only 'A' and 'AAAA' records (IPv4 and IPv6 address) but also an encrypted SNI key. If such a key is available we can use it to prove to the server (which set that key) which name we wanted, while eavesdroppers are none the wiser.

If the adversary can eavesdrop DNS they can already speculate from our query which host we wanted to talk to, but securing DNS is a problem for which there are known solutions.

[ Parent | on HN ]
Re:Cloudflare, Mozilla, Fastly, and Apple Working on Encrypt... by icebraining on Monday July 16, 2018 @05:16AM (#17539801)
So censors can stop this by preventing the use of (non-controlled) DoH and DoT servers?
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Re:Cloudflare, Mozilla, Fastly, and Apple Working on Encrypt... by namibj on Monday July 16, 2018 @05:38AM (#17539895)
No, the owner can sign the dns records and also sign the absence of a record, and if the censor tries to tell the browser that there is no SNI key, without being able to produce the signature to prove that, the browser can just treat this as an MITM attack. This only work on signed DNS entries though.
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Re:Cloudflare, Mozilla, Fastly, and Apple Working on Encrypt... by icebraining on Monday July 16, 2018 @05:47AM (#17539933)
But they just want to block it, so if the browser and/or app treats it as a MITM attack, that's fine from the censor's POV.
[ Parent | on HN ]
Re:Cloudflare, Mozilla, Fastly, and Apple Working on Encrypt... by namibj on Monday July 16, 2018 @01:31PM (#17543094)
There is a difference between inciting end point devices to drop down to less secure protocols, and alerting the user that you are running an active attack.
[ Parent | on HN ]