As Ars Technica first reported on Friday, users on social media started complaining earlier this week that YouTube ads were triggering their anti-virus software. Specifically, the software was recognizing a script from a service called CoinHive. The script was originally released as a sort of altruistic idea that would allow sites to make a little extra income by putting a visitor’s CPU processing power to use by mining a cryptocurrency called Monero. This could be used ethically as long as a site notifies its visitors of what’s happening and doesn’t get so greedy with the CPU usage that it crashes a visitor’s computer. In the case of YouTube’s ads running the script, they were reportedly using up to 80 percent of the CPU and neither YouTube nor the user were told what was happening.

Source: Hackers Hijacking CPUs to Mine Cryptocurrency Have Now Invaded YouTube Ads