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Comment by alecbenzer | Hacker News Reader

What's the point of confidentiality for DNS? Can't an attacker pretty easily get IP-to-DNS mappings to discover who you're talking to? I guess not in the case of VPNs/TOR?

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DNS hijacking is real and very annoying. The main benefit of these protocols is in the integrity of the DNS resolution data. It allows you to use any DNS server you want, without having your ISP modifying their responses.

Here is my story why I tried dnscrypt: https://medium.com/@nykolas.z/ending-dns-hijacking-with-dnsc...

Not in the case of Tor, but also not in the case of almost all/most cloud hosted services.

For example, consider that Cloudflare proxies about 10% of the Internet. Well, if you request a site they proxy, and DNS is in the clear, it's obvious who you are connecting to.

But if you request a site and the DNS is encrypted, you could be visiting any one of 10% of the sites out there.

Similarly, if hosting on AWS or Google Cloud platform, there's a LOT of other services hosted in those IP blocks, and IPs change frequently, so there's a significant degree of ambiguity.

This is all in addition to fixing the threat of DNS leakage for VPN/Tor connections.

> Cloudflare proxies about 10% of the Internet

... and strips SSL off on their side, so 10% of internet is, in fact, MITMed.

Be fair, this is configurable. So only 9.9% of the internet is probably MITMable.

What is configurable, apart from not using CF?

CloudFlare's customers can choose whether the backhaul, between CloudFlare and their own web servers, is HTTP, HTTPS with a CloudFlare issued private certicate, or HTTPS using publicly trusted certs from the Web PKI.

If you choose either of the latter two options, bad guys can't MITM you, the middle option has the benefit that they can't even MITM you by subverting a public CA (since only CloudFlare's own certs are trusted) the latter option has the benefit that you can "just" switch off CloudFlare and your site now works as an ordinary HTTPS site with no changes, if you ever want to do that.

In all those options, CF still terminates (strips) SSL from user traffic to plaintext, on their platform, hence MITM by Cloudflare.

And other large parts of the internet are "MITMed" by AWS, Heroku, Microsoft Azure or other hosting companies then. For some reason people don't make the same argument in every thread about AWS though.

Well, AWS does not mess with html code, like this:

https://stackoverflow.com/questions/22775065/cloudflare-add-...

It's just my gut feeling, that CF might abuse its unique position, having access to large part of internet traffic in plaintext. What other CDN gives free services? Hint, why Google Analytics is free?

Is Cloudflare a hosting company?

They are a CDN, they are storing data and delivering traffic under contract with the site owner. That's not strictly a hosting company, but that's pretty much irrelevant: They see traffic because the site owner has chosen and contracted them to provide a service that requires them to see traffic. The same way that traffic flows through AWS load balancers because the site owner configured that, or through the servers of a traditional hosting company because the site owner choose to host there.

One certainly can argue against Cloudflare specifically, or against centralization in general, but IMHO "they see traffic" isn't a very useful argument on its own.

Defaults matter. So you are probably right.

The majority of the Internet is MITMed nowadays.

... except that SNI isn't encrypted.

Good point - I totally forgot about that.

So yeah - it mostly only matters for VPN/Tor traffic.

Not yet, but encrypted SNI is on the way.

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