An ongoing security investigation by Socket's John Tuckner (via Bleeping Computer ) has discovered a search-hijacking campaign that involves 319 Chrome extensions with a combined 13.4 million downloads. The malicious extensions redirect search queries through tracking servers to generate advertising revenue from Bing and Yahoo.

It's more than double from Tuckner's April report that found "only" 57 Chrome extensions and 6 million downloads.

According to Tuckner, the malicious extensions are usually found on websites advertising tools that are labeled as "PDF converter", "AI search", or "safe search".

"These extensions were created by a handful of organized operators all working from the same idea: quietly take over the browser's default search engine, route every query through a suspicious proxy server, and collect partner referral payments from Yahoo or Bing under a syndication partner ID," Tuckner wrote.

The extensions apparently aren't found on the official Chrome Web Store either.…