A hacker added code to several web sites of CBS’s Showtime network that stole computing power from online visitors in order to mine digital currencies, offering a new twist on illicit profiteering from the boom in cryptocurrencies.
The exploit was discovered over the weekend and the unauthorized code was removed by Monday, tech news site The Register reported. Showtime’s popular shows include Homeland, Billions, and Shameless.
New coins in digital currencies like bitcoin and ethereum are created through the number crunching of mathematical calculations that verify transactions. That typically requires banks of high-powered computers gobbling huge amounts of electricity–and cutting into the profits of “mining” the new coins. The unknown hacker or hackers used the CBS cbs unit’s web sites to get around that cost by, in effect, hijacking the processing power of visitors to the web site to run a mining program for a digital currency called Monero.
More from FORTUNE
The code was placed in sections of the web site that appeared to be part of analytics software from online data analysis firm New Relic.
Get Data Sheet, Fortune’s technology newsletter.
Showtime declined to comment to Fortune.
New Relic newr said it was not responsible for the hacking. “We take the security of our Browser Agent extremely seriously and have multiple controls in place to detect malicious or unauthorized modification of its script at various points along its development and deployment pipeline,” New Relic said in a statement. “Upon reviewing our products and code, the HTML comments shown in the screenshot that are referencing newrelic were not injected by New Relic’s agents. It appears they were added to the website by its developers.”
(Updated on Sept. 26 with comment from New Relic.)