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Researchers identified a campaign involving 19 malicious browser extensions distributed through the Google Chrome Web Store and Microsoft Edge Add-ons marketplace, with reported installations exceeding 2.3 million users. Fourteen extensions were published as apparently legitimate software, while five were acquired from their original developers and later updated with malicious functionality, leaving users unaware that ownership and code had changed.
The extensions contacted command-and-control infrastructure to retrieve replaceable modules, bypassed Content Security Policy controls, and injected code into targeted web pages. They could steal credentials, payment data, Facebook and LinkedIn information, browsing history, cryptocurrency assets, and hardware-wallet seed phrases; some also overlaid pages with ClickFix lures that impersonated browser-update notices and persuaded victims to run malicious commands, potentially extending compromise beyond the browser.
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5 events from the most recent confirmed update back to the earliest known activity.
Researchers identified 16 malicious modules that could steal web-form credentials and payment data, Facebook and LinkedIn data, browsing history, cryptocurrency assets, and hardware-wallet seed phrases. Other modules replaced page content with ClickFix prompts designed to persuade victims to run malicious commands outside the browser.
At the end of August, researchers reported finding 18 malicious Google Chrome extensions and one malicious Microsoft Edge extension. They assessed that the 19 extensions were likely part of one campaign because of similarities in their malicious code and techniques.
A Koi Security report stated that Google and Microsoft had trusted malicious extensions that were installed by 2.3 million users.
The operators added malicious functionality to the extensions through subsequent updates, including automatic Chrome updates. The extensions contacted command-and-control servers for changeable malicious modules and disabled Content Security Policy protections to inject code into victims' visited pages.
The operators created 14 extensions that initially offered their advertised legitimate functions and acquired five legitimate extensions from their developers, including their existing user bases. Users were not notified when ownership changed.
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Researchers uncovered the **Superior** campaign, in which attackers distributed 18 malicious Chrome extensions and one Microsoft Edge extension that stole cryptocurrency-wallet secrets, credentials, browser data, and social-media sessions. The operator reportedly acquired legitimate extensions—or first published benign versions—then used automatic extension updates to install a modular malware framework after building an install base; the activity may have begun in early 2024. The extensions used encrypted persistent WebSocket connections for command-and-control, received rotatable infrastructure endpoints, removed page Content Security Policy headers, and injected malicious scripts into sites victims visited. Modules supported wallet draining, seed-phrase phishing, exchange-session theft, form and credential capture, browser-history collection, and ClickFix-style fake-update lures. Google removed the identified Chrome extensions, but an affected Edge extension remained available at reporting time; users should remove affected extensions, change passwords, revoke active sessions, and move cryptocurrency to newly created wallets.
Sep 4, 2026
Researchers reported multiple **malicious browser extension** campaigns abusing official add-on ecosystems to steal data and hijack accounts. One operation tracked as **GhostPoster** hid malicious logic inside seemingly benign PNG image files, a technique used to evade typical extension review and static checks; follow-on infrastructure analysis linked the activity to at least **17 additional extensions** using the same backend and tactics, with **~840,000 installs** and some extensions active for up to **five years**. The campaign reportedly started on **Microsoft Edge** and later expanded to **Chrome and Firefox**, emphasizing stealth and long-term persistence over rapid spread. Separately, Socket researchers identified **five malicious Chrome extensions** impersonating enterprise platforms (*Workday, NetSuite, SuccessFactors*) to enable **session hijacking and account takeover**. The extensions were described as working together to **steal authentication tokens/cookies**, **block incident response** by manipulating the DOM to interfere with security administration pages, and perform **cookie injection** to take over sessions; most were removed from the Chrome Web Store but remained available via third-party download sites. In response to the broader extension abuse, **Mozilla and Microsoft** removed identified add-ons from their marketplaces, but already-installed extensions remain a risk and require **manual removal**.
Jun 29, 2026
Multiple **malicious Chrome/Chromium extensions** were identified abusing the Chrome Web Store to steal data from users and enterprises. Two previously legitimate extensions—**QuickLens** (`kdenlnncndfnhkognokgfpabgkgehodd`) and **ShotBird** (`gengfhhkjekmlejbhmmopegofnoifnjp`)—reportedly turned malicious after **ownership transfers**, enabling downstream compromise through injected code and data harvesting. In the QuickLens case, researchers reported the malicious update preserved expected functionality while adding capabilities to **strip security headers** (e.g., `X-Frame-Options`) and facilitate script injection that can bypass **Content Security Policy (CSP)** protections, expanding the attacker’s ability to make cross-domain requests and collect sensitive information. Separately, Microsoft reported a campaign of **counterfeit “AI assistant” browser extensions** distributed via the Chrome Web Store (and therefore also impacting Microsoft Edge environments that allow Chrome extensions), which allegedly affected **20,000+ enterprise tenants** and amassed roughly **900,000 installs**. These extensions impersonated legitimate AI productivity tools and harvested **ChatGPT/DeepSeek conversation histories**, visited URLs, and browsing telemetry, staging data for exfiltration to attacker-controlled infrastructure. Another Chrome Web Store threat involved a fake **imToken**-branded extension (“lmΤoken Chromophore”) that masqueraded as a benign tool but redirected victims to phishing infrastructure to steal **seed phrases and private keys**, using tactics like hardcoded remote configuration (via JSONKeeper) and decoy navigation to the legitimate `token.im` site after credential capture.
Jun 29, 2026