Frequent visitors to popular torrent site The Pirate Bay are up in arms after the site secretly added a feature to the site that sapped users' CPU resources to mine cryptocurrency.

While file-sharing websites and other shady corners of the web are always risky places to visit, some of the biggest ones have earned a reputation as relatively safe. While the currency-mining script — which TPB apparently implemented as part of a push to find a new source of income — doesn't pose much of a risk to the site's visitors, hijacking your users' processors to make money for yourself without telling them is not a great look.

Prospective pirates found somebody was stealing from them, and they weren't happy.

Torrent Freak reported over the weekend that TPB users discovered the script after noticing "that their CPU usage increased dramatically when they browsed certain Pirate Bay pages."

The software is provided by a service called Coinhive, and lets websites grab spare CPU cycles from anyone viewing their pages and use them to mine Monero, a Bitcoin-style cryptocurrency which has been around since 2014. According to Torrent Freak the miner was throttled low and only appeared on certain TPB pages, but its impact to the speed of a visitor's computer was immediately noticeable.