Hackers have placed advertisements on YouTube that secretly take control of computers to mine cryptocurrency.
Security researchers identified a surge in incidents of hijacking, affecting thousands of victims, and traced the problem to certain Google ads on YouTube and other sites. If the user clicked on the ad, they were directed to a page that showed legitimate advertisements but their computers became infected with Coinhive, code that is used to mine monero, a cryptocurrency similar to bitcoin that is worth £200 a unit.
“We detected an almost 285 per cent increase in the number of Coinhive miners,” said Chaoying Liu and Joseph Chen from Trend Micro, the data security company. Their blog post said that the mining software used up 80 per cent of the victims’ computing power.
The value of many cryptocurrencies, including monero, has increased in the past couple of years, making this sort of attack more lucrative. Cryptocurrencies are “mined” when people use their computer power to verify transactions on a blockchain and receive digital coins as a reward. The process requires significant processing power.
Sources close to Google, which owns YouTube, said criminals were changing tactics to get around the company’s checks. A spokesman said Google was monitoring the abuse and blocked malicious ads in less than two hours.