MacSync Malware Evolves to Steal Cryptocurrency and Conceal Components in iCloud
MacSync malware targeting macOS users has received a significant upgrade, according to experts from Kaspersky. The updated variant now operates as part of a combined payload that includes both a stealer and a backdoor, enabling theft of passwords, cryptocurrency wallet data, and persistent remote access for attackers.
The malicious program first appeared in 2024–2025 as a fork of the AMOS stealer. The September 2026 sample introduces a more complex, multi-stage infection chain. The attack typically starts when a user downloads what appears to be a legitimate application, such as a document collaboration service or cryptocurrency wallet.
In some cases, attackers deliver one component through a publicly accessible iCloud calendar entry in ICS format. This novel delivery method supplements conventional loaders that have apparently become insufficient for the threat actors.
Once launched, MacSync mimics the downloaded application and prompts for administrator credentials. It then displays a fake macOS notification claiming the program is damaged and suggesting it be moved to the Trash. In reality, the stealer remains on the system and begins collecting browser history, cookies, logins, passwords, Telegram data, cryptocurrency wallet information, and SSH/ZSH settings.
A second component disguised as Finder functions as a backdoor. Through this component, attackers can execute arbitrary code, exfiltrate specific files, install browser extensions, and replace the legitimate Ledger application with a malicious version. The primary goal of this substitution is cryptocurrency theft.
Security researchers recommend downloading applications exclusively from verified sources and treating unexpected administrator password requests with caution.
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