What is BitTorrent?
BitTorrent is the name of a communication protocol for peer-to-peer file sharing (P2P) which is used to distribute data and electronic files over the Internet. BitTorrent is one of the most popular protocols for transferring large files, such as digital video files containing TV shows or video clips or digital audio files.
How it works
Rather than downloading a file from a single source server or multiple mirror servers, BitTorrent allows users to join a group of hosts to upload to/download from each other the different packets or pieces that make up the file simultaneously As each peer receives a new piece of the file, it becomes a source (or seed) of that piece for other peers, relieving the original seed from having to send that piece to every computer or user wishing a copy.
This way, each group of users relieves each other in the file distribution task, freeing up others to share new files. All this results in a more effective system for sharing files over networks with lower bandwidth. Additionally, BitTorrent trackers provide a list of files available for transfer, and allow the client to find seeds who may transfer the files.
Risks
Some ransomware variants, such as TorrentLocker, take advantage of P2P networks to spread by using fake file descriptions. TorrentLocker, discovered in 2014, is a ransomware Trojan targeting Microsoft Windows systems. It encrypts the victim's files in a similar manner to CryptoLocker by implementing a symmetric block cipher AES.
The Pirate Bay is one of the most popular torrent sites in the world. This site has been shut down and then resurrected multiple times under different names. In 2015, a gang of cyber-crooks took advantage of the confusion to create a The Pirate Bay mirror site and redirect multiple WordPress sites to it by injecting them with malicious code. These malicious URLs didn't lead to a download site.When someone clicked on the link, a malware infected their computer and recorded the owner’s information, such as bank details or passwords, sending them later to the criminals.
In that very same year, uTorrent, one of the most popular BitTorrent clients on the web, was the source of huge controversy, with many users complaining that the tool installed a PUP (potentially unwanted program) on their systems without their knowledge. That program was EpicScale, a Bitcoin mining software that uses up system resources.
Preventive measures
- Download programs from official and legitimate sites rather than P2P file-sharing sites.
- If, despite all recommendations not to, you choose to use one of those sites, there are forums such as Torrent Freak where you can find the most up to date information on potential threats and safe torrenting sites.
- Be sure to pay close attention to the dialog boxes displayed by the installation wizard of all the programs you install, in case someone tries to slip you unwanted software capable of using up your computer's resources or carrying out other malicious actions.
- Finally, protect yourself from all attempts to introduce malware into your computer by using a professional antivirus solution capable of scanning all downloads and the files you install.
