ModHeader

Hidden Spy for 1.6 Million Users: Popular Browser Extension ModHeader Secretly Collected Browsing History

Google and Microsoft have removed the popular ModHeader browser extension from the Chrome Web Store and Microsoft Edge Add-ons after security researchers discovered a hidden mechanism designed to secretly collect users' browsing history. The extension, which had approximately 1.6 million installations, allowed developers to modify HTTP headers for testing and debugging purposes but contained a dormant data-collection module in its legitimate codebase. British firm Stripe OLT confirmed that the suspicious code was part of the genuine signed build rather than a fake version. Although the history-stealing functionality remained inactive due to an empty internal browser list, the extension still transmitted telemetry data and could have been activated remotely via a simple update. Experts recommend immediate removal of the extension, replacement of any credentials entered through it, and blocking of the domains stanfordstudies[.]com and extensions-hub[.]com.