Cybercriminals Hide Malware in Fake Claude Code Installation Command Targeting macOS Developers

Cybercriminals are distributing the MacSync infostealer by embedding malicious commands in fake installation tutorials for Claude Code. The campaign relies on sponsored search ads and counterfeit documentation pages that appear when developers look up official setup instructions. Victims are instructed to paste an obfuscated command into the macOS Terminal that uses Base64 encoding to conceal the download server and disables certificate validation. Once executed, the command retrieves MacSync, which steals passwords, session cookies, SSH keys, cloud credentials, and developer configuration files. Stolen tokens can bypass multi-factor authentication and grant attackers direct access to accounts and repositories. Security experts advise installing Claude Code exclusively through official channels and immediately isolating any compromised Mac while revoking all sessions and rotating credentials from a trusted device.

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Cybercriminals are hiding malware inside a fake installation command for Claude Code, targeting developers on macOS. The campaign uses sponsored advertisements and counterfeit web pages to reach users searching for legitimate setup instructions.

The attack begins when a victim searches for installation guidance and clicks a sponsored result that mimics official documentation. The fraudulent page displays a step-by-step tutorial and directs the user to copy and paste a command directly into the macOS Terminal.

The command employs obfuscation techniques, including Base64 encoding, to conceal the address of the attacker-controlled server. It also disables digital certificate validation during the connection, allowing the download to proceed without security checks.

After execution, the command retrieves MacSync, an infostealer designed to harvest sensitive data stored on macOS systems. The malware specifically targets passwords, session cookies, SSH keys, cloud service credentials, and configuration files commonly used by developers.

Stolen authentication tokens can enable attackers to access user accounts and code repositories without triggering multi-factor authentication prompts.

Users are strongly advised to install Claude Code only through official documentation and to avoid any commands that hide URLs or disable security validations. Anyone who has already run the malicious instruction should isolate the affected Mac, revoke active sessions, and change all passwords, tokens, and SSH keys from a trusted device.

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