Over here, it came up that the operator of a web service can find out the real IP address of a Tor Browser user by simply letting the user resolve a subdomain via a HTML element and logging who (source IP address) tried to resolve that subdomain on the web service's name server.
I don't see why Tor's strategy of resolving TLDs would be any different from its strategy of resolving subdomains.
I was under the impression (googled it some time ago) that resolving DNS is none of the Tor Browser's business and if we only take a look at the Tor Browser's traffic, in fact none of the business of any application on the user's computer. The Tor Browser would just request the document
http://stackexchange.com/ from the used exit node γ through α and β (α being the entry node) and then once it got it see that in order to display the website, it needs the document
http://stackexchange.com/topbar/get-unread-counts?_=1475324641346 so it would request that from γ through α and β. Finding out that the IP address of
220.127.116.11 would be the job of γ. Now, if the document
http://stackexchange.com/ embedded the resource
https://security.stackexchange.com/image.png, the Tor Browser of course wouldn't go about asking the name server of
stackexchange.com what the IP address of
security.stackexchange.com is and figure out that it's
18.104.22.168. This, again, would be the job of γ.
However, according to George Y., this isn't true. Instead, as I took it from him (please correct me if I misunderstood him), the Tor Browser asks the name server of
stackexchange.com about the IP address of
security.stackexchange.com, finds out that it's
22.214.171.124, and then requests
http://126.96.36.199/image.png from γ. (Yes, of course the Tor Browser probably doesn't to that itself but instead asks the local nameserver which then iteratively resolves the DNS entry but this doesn't really matter because (in the case of IPv4) it doesn't change the IP address.)
Similarly, I think this would mean that for the initial request (let's assume the
.com nameserver is already known and we don't need to go ask a root name server for it) of
http://stackexchange.com/ would require the Tor Browser to first resolve
188.8.131.52 and then to request the document
http://184.108.40.206 from γ.
If this is correct, this would mean that the operator of the
.com nameserver can create a list of all websites which were visited by a user with a certain IP address. A state authority can force the operator of the
.com nameserver to keep and share with it a log of requests consisting of the domain resolved and the source IP address. That state authority of course can also force the user's ISP to tell it who was assigned that IP when the request was made, therefore revealing which servers which user communicated with.
Is this true? If (hopefully) not, where is the mistake?