a) Infiltrating chats where people are more likely to share sensitive information / trust the people they're talking to
b) Poor configurations/ setups on either the client or server (client browser bundle has noscript, but it's not on the strictest settings, js is enabled iirc)
c) Exploitation of client or server due to out of date versions, things like that
Historically I think it's always fallen into one of these cases - and not just what the FBI etc say publicly but we've seen these exploits ITW. I wouldn't be surprised if the NSA and other agencies have the power to deanonymize TOR users but if it were trivial why is the majority of TOR traffic still going towards illegal content? Last I read (a paper a year ago) TOR is still primarily all about drugs, followed by child pornography (mostly drugs though iirc). If they can track all of these people by breaking TOR completely... why don't they?
