GhostPoster: Malicious Firefox Add-ons Drive 2025 Supply-Chain Breach
In late 2025, security researchers at Koi Security uncovered a widespread supply-chain malware campaign named "GhostPoster." This campaign weaponized 17 Mozilla Firefox browser add-ons, leveraging benign logo files to conceal malicious JavaScript that hijacked affiliate links, injected tracking codes, and orchestrated click and ad fraud operations. The compromised extensions had garnered over 50,000 downloads before Mozilla intervened to remove them from its add-on repository, but users were already exposed to extensive privacy intrusions and potential data exfiltration. The GhostPoster incident underscores a growing trend of exploiting trusted browser extension ecosystems for mass infection and financial fraud. With attackers increasingly targeting supply-chain vectors and browser add-ons, organizations and individuals must reevaluate extension vetting processes amid surging regulatory scrutiny and evolving adversary techniques.
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