From zdnet.com
Academics have come up with a new technique that leaks data about users’ browsers; enough to defeat anti-fingerprinting systems and privacy-preserving browser extensions to provide ways to identify users by their browser and underlying platform in a way that has not been done before.
Called “JavaScript Template Attack,” this new technique revolves around the concept of JavaScript properties and the default values that browser engines return for basic JavaScript queries seeking the value of a certain property.