Userbase

The exploit works by abusing Chromium's Browser Fetch API to open a service worker that remains persistently active. A malicious website can trigger it through JavaScript, creating a connection that can be used "for monitoring some aspects of a user's browser usage and as a proxy for viewing sites and launching denial-of-service attacks," reports Ars.

Depending on the browser, those connections "either reopen or remain open even after it or the device running it has rebooted," effectively turning the device into part of a "limited botnet."