Polyfill Supply Chain Attack Injects 100,000+ Websites with Malware via CDN Assets
Polyfill.js is a Javascript library that helps old browsers run new modern features which these old browsers do not support natively. The library is popular among developers for helping them offer consistent user experience regardless of the browser environment the user is using. In February 2024, a Chinese company bought the domain polyfill.io and the Github account associated with it. Since then, they’ve been serving malware via cdn.polyfill.io as pointed by the team at Sansec.