Malicious Browser Extensions Used for Stealthy Data Theft and Account Takeover
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.
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