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Socket Threat Research title art for Searchjacked, a neon search bar on a dark background.
Image: Socket (fair use).

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Socket Says 319 Search-Hijacking Browser Extensions Reach About 13.4 Million Users, Routing Every Query Through Operator Proxies for Yahoo and Bing Referral Fees

Most of the extensions are unlisted Manifest V3 search-provider overrides with no permissions and no UI, pushed through ads. Socket published Censys and Urlscan hunts, named operators from Intango to System1, and argued the redirects could be switched from syndication results to phishing or malware lures per request.

James Whitford, ToolsAustin6 min read

AUSTIN - Socket said Thursday that 319 browser extensions, installed by about 13.4 million users, exist mainly to take over a browser's default search engine, send every query through an operator-controlled proxy and collect partner referral payments from Yahoo or Bing.

The research expands on Socket's earlier work with 264 newly identified extensions that add about 8.7 million users. "An extension whose only function is to intercept searches users could have made anyway, that is purposefully hidden from indexing, promoted through low-value advertising listings, and provides no additional value should be considered malicious by definition," the report said.

How the hijack works

Many of the extensions are little more than a Chrome Manifest V3 file with chrome_settings_overrides.search_provider pointed at the operator's domain. They request no permissions, ship no background service worker, no content scripts and no UI. Changing the default search provider triggers a prompt at install time, Socket said, but the prompt does not clearly say where searches will go.

Socket diagram showing how hijacking extensions override default search through an operator proxy.
Image: Socket (fair use).Browser to operator proxy to Yahoo, Bing or somewhere else.

Queries do not go straight to Yahoo or Bing. They hit the operator's search server first, which records the query, often with a unique identifier, then chooses the redirect. Yahoo tracking uses hspart and hsimp parameters; Bing uses a PC partner code and a PTAG sub-ID. In one Predator Search case (extension ID odkcfoohjiicbelloepgcomekdknchjh, 50,000 users), six identical searches through the same proxy ended in four different places: Yahoo with partner tags, a landing page on searchlio.net, a hop through searchtosearch.com to mcftink.com before Yahoo, and a Cloudflare error page.

Hidden from the store, pushed by ads

A majority of the extensions Socket found are unlisted in the Chrome Web Store, so they do not appear in store search. Users reach them through paid advertising on Google Ads, Bidbrain and similar networks, often as pop-overs or pop-unders for "PDF converter," "manual finder" or "safe search" tools.

Chrome Web Store search returning no results for an unlisted search-hijacking extension ID.
Image: Socket (fair use).An unlisted extension ID that does not appear in store search.

The pattern goes back a decade. A Russian-language "Yandex search" extension published in 2016 reached 200,000 users before it was taken down. HermesTab in 2017 totaled 400,000 users across two Yahoo new-tab hijackers. Intango LTD has published about 111 extensions totaling roughly 2.2 million installs across about 279 domains. Tightrope Interactive ran about 200,000 Google ads across 307 domains. The 2024 SecuryBrowse wave, covered in Socket's earlier research, put 58 security-branded extensions in front of about 4.9 million users. Starting in April 2025, 37 Bing-redirect extensions appeared; 15 seemingly independent publishers pushed updates within the same four days in June 2026 and shared the same Bing partner tags.

Google Ads Transparency view of BrightWorks Technology LLC ads for getsimplepdfsearch.com and related extensions.
Image: Socket (fair use).Ads Socket tied to BrightWorks Technology LLC for search-hijack install pages.

Socket published Censys and Urlscan queries defenders can reuse, including pages that mention both a Chrome Web Store detail URL and "default search," and Urlscan scans that redirect onto a Chrome Web Store link while containing that phrase. From the store listing, teams can pull the extension ID, check whether it is unlisted, open the privacy policy for a company name, and search Google Ads Transparency for the landing-page domain. Socket named operators where it could, from Intango and Tightrope Interactive to BrightWorks Technology LLC / SilverEdge Systems LLC, Capital Intellect, System1, Perion Network, Free Planet VPN S.R.L and others, and left about 119 extensions totaling roughly 7.76 million users under unknown operators, including the SecuryBrowse and Bing-Search clusters.

For SOCs and desktop teams, the practical steps are inventory of installed Chrome, Edge and Firefox extensions against Socket's published set, alerts on new default-search overrides, and hunting for outbound search traffic that hits operator proxies before Yahoo or Bing. Removing an unlisted extension is often enough; the harder problem is the next advertising wave that replaces it.

Sources:


James Whitford covers SOC tooling, SIEM, SOAR, and detection platforms for SOCtember from Austin.

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