In some cases, extremely high CPU usage can be indicative of a malware infection. When you aren’t running any software or loading webpages, Lifewire shares that normal CPU or “central processing unit” usage should be around 1% to 5%. However, different types of malware can utilize your underused CPU without your consent in various ways, including mining for cryptocurrency.
According to Check Point Software, crypto-mining malware infects a computer and uses it to perform the seek for cryptocurrency blocks. Referred to as “drive-by mining,” Malwarebytes defines this practice as when “a piece of JavaScript code is embedded into a Web page to perform cryptocurrency mining on user machines that visit this page.”
In 2018, thousands of websites were compromised with crypto mining software, including U.S. and U.K. government websites through a third-party plug-in developed by Texthelp to help visually impaired users, called “Browsealoud.” For this type of malware, unsuspecting visitors to these legitimate websites experienced a sudden spike in their CPU usage when their browsers were open.
To review your CPU usage for any unusual activity on Windows, press Ctrl+Shift+Esc at the same time. In the left-side column, select Performance > CPU. For Mac users, you can view your GPU activity monitor by going to the Activity Monitor. To do this, launch Spotlight and seek “Activity Monitor.” Then, on the menu bar, select Window > CPU History. Both will show what percentage of power your browser is using, which should be less than 10%.
