MacSync

Fundamental Flaw in File Monitoring APIs Exposes Keystrokes and App Activity Across Windows, Linux, Android, and macOS

Researchers from Graz University of Technology demonstrated how built-in file change notification mechanisms can leak sensitive user activity without requiring elevated privileges. The affected subsystems include inotify on Linux, FileObserver on Android, ReadDirectoryChangesW on Windows, and FSEvents on macOS. On Linux the technique enables reconstruction of typed text with 93-100% accuracy by monitoring /dev/input/event4 timestamps. Android apps can break sandbox isolation to observe messaging events, while Windows monitoring of browser cache files reveals visited websites at 97.8% accuracy. Only partial mitigations have been deployed in Linux and Windows, with no fixes available for Android or macOS. Additional attacks remain possible, including detection of password prompts to facilitate phishing overlays.

MacSync Malware Evolves to Steal Cryptocurrency and Conceal Components in iCloud

Updated MacSync malware for macOS now arrives bundled with a stealer and backdoor, allowing attackers to harvest browser history, cookies, passwords, Telegram data, and cryptocurrency wallet details while maintaining persistent remote access. Discovered by Kaspersky researchers in September 2026, the new variant uses a multi-stage infection chain that begins with a fake application download, such as a document collaboration tool or crypto wallet. One component is delivered through a publicly shared iCloud calendar entry in ICS format, bypassing traditional loaders. After execution, MacSync requests administrator credentials, displays a fake macOS damage notification, and installs the stealer alongside a Finder-masquerading backdoor. The backdoor enables arbitrary code execution, file theft, browser extension installation, and replacement of the legitimate Ledger application with a malicious version to drain cryptocurrency funds. Users are advised to download software only from trusted sources and remain cautious of unexpected administrator password prompts.

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.