"What makes bot markets different from other dark web markets is that they are able to get large amounts of data about one person in one place," according to Marijus Briedis, chief technical officer of NordVPN.
"And after the bot is sold, they guarantee the buyer that the victim's information will be updated as long as their device is infected by the bot."
In their analysis, NordVPN researchers uncovered 667 million cookies, 81,000 digital fingerprints, 5,38,000 auto-fill forms, a lot of screenshots taken with various devices, and webcam pictures.
(With inputs from Reuters)