Cyber criminals have not only targeted American hospitals and UPS customers in recent weeks, but are now putting their focus on uTorrent and Vuze users who download music, movies and other media from the Internet for free.

Content is downloaded every day in the form of torrent files, which make it possible for users to save a massive file (like a movie or software, for instance) by linking to other users and downloading. The idea has been largely successful in trying to make downloads faster, as users obtain chunks of the file from many different sources rather than a single source. The cadre of users who link together to download a single file make up what’s known as a “swarm,” with “peers” uploading and downloading the file at the same time.

Downloading torrents is not illegal, though the method of downloading is so associated with illegally downloading copyright material that “torrenting” is now equated with piracy in many instances. The most popular programs for downloading torrents is are Vuze and uTorrent, which between them are estimated to have more than 100 million users around the world. (It’s possible that uTorrent alone has more than 100 million users, though the service does not provide official numbers.)  

Florian Adamsky, a research at the City University London, has published a new article in “Computers and Security” explaining that it’s now possible for hackers to subvert swarm downloads and almost all of the bandwidth power at work for their own gain, a process that essentially allows them to steal bandwidth.

“We reveal a simple exploit that allows malicious peers to receive a considerably higher download rate than contributing leechers, therefore introducing significant efficiency degradations for benign peers,” he wrote. “Our results show that 3 malicious peers can degrade the download rate up to 414.99% for all peers.”

Translation: It’d be faster to order a movie on Netflix and wait for it to arrive in the mail than to illegally download one from one of these infected swarms.

Adamsky told clients like Vuze and the also-popular transmission are especially vulnerable.

“Vuze is only partly affected as it allows pieces to be downloaded 64 times and then all further requests are rejected. Nevertheless we have listed Vuze as vulnerable since it is possible to reconnect and restart the attack,” Adamsy said. “If more of the clients would have a vulnerable client like Vuze or Transmission it would be possible to increase the average download time up ten times.”