More on DataSpii: How extensions hide their data grabs—and how they’re discovered

Enlarge / You can trust us! (credit: Irakli Kalandarishvili / EyeEm / Getty)

In our 5,000 word piece on “DataSpii,” we explained how researcher Sam Jadali spent tens of thousands of dollars investigating the murky Internet ecosystem of browser extensions that collect and share your Web history. Those histories could end up at sites like Nacho Analytics, where they can reveal personal or corporate data.

Here, we want to offer more detail for the technically curious reader on exactly how these browser extensions work—and how they were discovered.

Obscurity

Discovering which browser extensions were responsible for siphoning up this data was a months-long task. Why was it so difficult? In part because the browser extensions appeared to obscure exactly what they were doing. Both Hover Zoom and SpeakIt!, for instance, waited more than three weeks after installation on Jadali’s computers to begin collection. Then, once collection started, it was carried out by code that was separate from the extensions themselves.