Tipped off about the existence of the fake website by a friend, Julien Voisin downloaded the purported Tor Browser Bundle (torbrowser-install-3.6.3_en-US.exe) and managed to reverse engineer it.
What he discovered is that the malware can be commanded to download and upload files, update itself, make screenshots, execute system commands, reboot and restart, upload directories and get drives, and launch new connections.
The communication protocol runs on a hidden service on Tor, and Voisin even managed to get in touch with the botmaster.
"She/he told me that they are a small group (maybe from China) trying to catch pedophiles; by spreading the link to the fake website on pedo-boards, adding that one pedophile was already reported to cybertip (Canadian Centre for Child Protection's tipline)," he shared, but said that he doubts the story, as "the miscreant not only shiped a malware instead of the real TBB, but also replaced the donation page with his own BTC address."
The website had, surprisingly, still online (on torbundlebrowser.org), but I guess it won't be for much longer. It's more than likely that the person(s) behind it will move it to another, equally deceptive, domain.