Description

A malicious browser extension identified as CL Suite is targeting business accounts associated with Meta Platforms, specifically users of Meta Business Suite and Facebook Business Manager. Disguised as a productivity and verification-support tool, the extension is distributed through the Chrome Web Store and claims to assist users in handling account verification pop-ups and generating two-factor authentication (2FA) codes. However, security analysis revealed that its actual purpose is to harvest sensitive authentication data and internal business information, placing high-value advertising and enterprise accounts at significant risk. Technically, the extension requests extensive permissions within Google Chrome, allowing it to access and interact with Meta-related domains. Once installed, it captures Time-Based One-Time Password (TOTP) secrets — the cryptographic seeds used to generate 2FA codes. By exfiltrating these seeds to an attacker-controlled command-and-control (C2) server, the threat actors can continuously generate valid authentication codes, effectively bypassing 2FA protections even after passwords are changed. In addition, the extension enumerates business assets, including employee details, ad account data, email addresses, and payment configurations. The stolen information is structured into JSON payloads and transmitted to remote infrastructure, with some data reportedly forwarded to private channels on Telegram for real-time monitoring. The impact is severe for organizations relying on Meta’s advertising ecosystem. Compromised TOTP seeds enable persistent account takeover, financial fraud through ad account abuse, and potential data leakage affecting clients and partners. Organizations should immediately audit installed browser extensions, remove any unverified add-ons, rotate 2FA secrets, revoke active sessions, and transition to hardware-backed authentication such as FIDO2 security keys. Continuous monitoring of business account activity and strict browser extension governance policies are strongly recommended to mitigate similar supply-chain style threats.