When browsing onion websites e.g. discussion forums, quite regularly I will encounter links to clearnet http/https addresses along with an explicit Clearnet Warning along with the URL.
What is unclear to me is what precisely the warning is referring to. The frequency with which I see it makes me wonder if I'm misunderstanding the threats to browsing with TBB:
- Perhaps clearnet browsing reflects a threat to anonymity that is not had by "sticking to onion websites" only?
OR
- Does posting a clearnet link on an onion website give adversaries a new possible vector to exploit and deanonymise Tor users? That is, if the adversary can compromise the server hosting that domain, they have a honeypot for all visitors of this new URL, one which had not existed prior to the new link being created? I presume an individual accessing the URL with an appropriately con
OR
- Does the threat relate to exposing visitors to potential deanonymization via correlational attacks?
If explanations 2 or 3 are more correct, is it true to say that the Tor user who first accessed the clearnet URL and posted the link was not vulnerable (at least threat 3), whereas the Tor users who subsequently visit it are?
Moreover, will an appropiately configured TBB e.g. Javascript disabled, mitigate the majority of these dangers from the offset? I apologise for the peculiar question -- from the context in which read them, it seems that posting clearnet URLs is tantamount to a faux pas.
Previously related questions
These questions have been previously asked and although they relate to similiar topics, but do not explicitly address the question I am asking here:
- Which provides better security/anonimity: .onion or https?
- Is Tor's security compromised if other services are connecting in the clear? Relates to non-browser related activities
Refererheader in many cases, which will carry the .onion address of the hidden service (making it no longer hidden).