As the extensions ecosystem continues to evolve, we remain focused on empowering developers to build innovative experiences while keeping our users as safe as possible. Over the past few months, there has been a rise in malicious extensions that appear to provide useful functionality on the surface, while embedding hidden cryptocurrency mining scripts that run in the background without the user’s consent. These mining scripts often consume significant CPU resources, and can severely impact system performance and power consumption. The chart above shows a recent example of CPU overutilization from hidden coin mining in an extension. Until now, Chrome Web Store policy has permitted cryptocurrency mining in extensions as long as it is the extension’s single purpose , and the user is adequately informed about the mining behavior. Unfortunately, approximately 90% of all extensions with mining scripts that developers have attempted to upload to Chrome Web S...