
MacSync Malware Weaponizes iCloud Calendars in Advanced macOS Attack Campaign
MacSync, a Swift-based infostealer malware targeting macOS systems, has evolved to use public iCloud calendar events as a novel command and control mechanism to deliver fresh payloads. First emerging in April 2025 and derived from the AMOS stealer family, MacSync has been distributed through social engineering campaigns including ClickFix attacks, fake applications, and fraudulent crypto wallets. The malware's latest iteration includes a new Objective-C backdoor module that disguises itself as Finder and establishes persistence through LaunchAgent modifications, targeting browser credentials, crypto wallets, SSH configurations, and system information while evading detection by terminating macOS notification processes. This incident highlights the growing sophistication of macOS-targeted malware as attackers increasingly focus on Apple's ecosystem, exploiting trusted cloud services like iCloud for command and control operations while incorporating advanced evasion techniques that bypass traditional security controls.
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