Encrypted Client Hello • Hacker News Board

Re: Encrypted Client Hello

#11

Post by cosmosgenius » Fri, Sep 29, 2023, 2:32 PM UTC

makeworld wrote: post #2

If I host my website on a VPS, is ECH possible? Seems like it's only useful when IP addresses are shared across a bunch of sites.

ECH can be enabled depending on the Terminating TLS server used. (not sure which one implements it now) But you are right in the sense its used for multiple sites to one IP. Essentially ECH is protection for SNI, ALPN, which are plaintext in non-ECH.

Re: Encrypted Client Hello

#12

Post by Al0neStar » Fri, Sep 29, 2023, 2:59 PM UTC

Everytime someone mentions Cloudflare, i think about this article [0].

[0] https://blog.cr.yp.to/20230609-turboboost.html

Re: Encrypted Client Hello

#13

Post by kreetx » Fri, Sep 29, 2023, 3:14 PM UTC

TrueDuality wrote: post #6

politelemon wrote: post #4

I'm not seeing it. It looks contradictory what they're saying. > This means that whenever a user visits a website on Cloudflare that has ECH enabled, no one except for the user and the website will be able to determine which website was visited. But if you look at the inner/outer SNI part: > The outer SNI is a common name that, in our case, represents that a user is trying to visit an encrypted website on Cloudflare.…

You're absolutely right, Cloudflare will still see it. That doesn't make this a bad improvement though. You don't have to use Cloudflare to support it, but it helps obscure which site is being visited by the nature of Cloudflare hosting so many different sites. So what does this actually protect against? Who will this benefit? Mostly people in censored countries and companies. This removes the last piece of informati…

What is wrong with DoH?

Re: Encrypted Client Hello

#14

Post by galadran » Fri, Sep 29, 2023, 3:19 PM UTC

politelemon wrote: post #4

I'm not seeing it. It looks contradictory what they're saying. > This means that whenever a user visits a website on Cloudflare that has ECH enabled, no one except for the user and the website will be able to determine which website was visited. But if you look at the inner/outer SNI part: > The outer SNI is a common name that, in our case, represents that a user is trying to visit an encrypted website on Cloudflare.…

The point is that network operators can't tell which website the user is visiting, as it could be any of the sites hosted by the ECH provider.

In this case, Cloudflare are acting as the ECH provider and as they already host the websites, they already see the connection plaintext.

Re: Encrypted Client Hello

#15

Post by discardedrefuse » Fri, Sep 29, 2023, 3:20 PM UTC

I feel like this is only possible because Cloudflare is already so huge. If this becomes widely adopted, anyone who wants to offer "private" access to their site will have to move through Cloudflare. This can't be good.

Re: Encrypted Client Hello

#16

Post by dilyevsky » Fri, Sep 29, 2023, 3:21 PM UTC

It seems like the same result could easily be achieved by widespread Domain Fronting support (e.g set sni to cloudflare-sekrit.com and Host: header to the actual domain). Can someone explain why this wasn't adopted more widely (I know CF, for example, disabled theirs)?

Re: Encrypted Client Hello

#17

Post by galadran » Fri, Sep 29, 2023, 3:22 PM UTC

discardedrefuse wrote: post #15

I feel like this is only possible because Cloudflare is already so huge. If this becomes widely adopted, anyone who wants to offer "private" access to their site will have to move through Cloudflare. This can't be good.

Any provider can deploy ECH, it's standardized at the IETF. Cloudflare are just first.

Re: Encrypted Client Hello

#18

Post by galadran » Fri, Sep 29, 2023, 3:23 PM UTC

dilyevsky wrote: post #16

It seems like the same result could easily be achieved by widespread Domain Fronting support (e.g set sni to cloudflare-sekrit.com and Host: header to the actual domain). Can someone explain why this wasn't adopted more widely (I know CF, for example, disabled theirs)?

I believe CF and others buckled under pressure from major websites which didn't want to be used as fronts for other website's traffic. ECH fixes this because individual sites get to opt-in to using it.

Re: Encrypted Client Hello

#19

Post by jeffmcjunkin » Fri, Sep 29, 2023, 3:28 PM UTC

dilyevsky wrote: post #16

It seems like the same result could easily be achieved by widespread Domain Fronting support (e.g set sni to cloudflare-sekrit.com and Host: header to the actual domain). Can someone explain why this wasn't adopted more widely (I know CF, for example, disabled theirs)?

For whatever reason, Domain Fronting is considered more of an attack behavior, used by red teamers and penetration testers. Doubling down on that behavior likely didn't seem as appealing from a PR perspective.

Re: Encrypted Client Hello

#20

Post by discardedrefuse » Fri, Sep 29, 2023, 3:34 PM UTC

galadran wrote: post #17

discardedrefuse wrote: post #15

I feel like this is only possible because Cloudflare is already so huge. If this becomes widely adopted, anyone who wants to offer "private" access to their site will have to move through Cloudflare. This can't be good.

Any provider can deploy ECH, it's standardized at the IETF. Cloudflare are just first.

Thanks for the info. This feels a little better. I can still envision only a handful of "providers" becoming the defacto gatekeepers to a private web. I'm gonna have to give this some more thought though.