A malvertising campaign used sponsored Google search results for Anthropic's Claude to lure macOS users to a legitimate shared conversation page on claude.ai, where they were socially engineered into running a malicious terminal command. Huntress reported that the command fetched MacSync, a multi-stage macOS infostealer and remote access trojan that chains a zsh loader, in-memory AppleScript theft, a persistent Mach-O RAT, and a helper component designed to abuse Screen Recording permissions.
The malware was built to steal a wide range of data from infected Macs, including browser data, Keychain secrets, saved passwords, Telegram sessions, SSH and cloud credentials, and cryptocurrency wallet recovery phrases. The operation also used repeated TCC permission prompts, fake "Apple Support" messaging, and trojanized cryptocurrency wallet applications to deepen access, maintain persistence, and expand theft beyond initial credential harvesting.

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2 events from the most recent confirmed update back to the earliest known activity.
In July, a Huntress customer clicked a sponsored Google Ads result for "How to Install Claude on a Mac" and was redirected to a legitimate shared claude.ai conversation page used as a lure. The page, presented under the display name "Apple Support," instructed the user to paste a malicious curl command into Terminal, which delivered the MacSync malware.
After investigating the incident, Huntress analysts reconstructed the malware loader request from Elastic telemetry and retrieved a sample directly from the attacker's servers using a spoofed macOS User-Agent and a static api-key. Their analysis identified MacSync as a six-stage macOS infostealer and RAT chain.
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