Threat actors are increasingly using weaponized .dmg files disguised as legitimate macOS software installers to deliver infostealer malware, with campaigns relying heavily on social engineering to convince users to bypass Apple Gatekeeper and other trust prompts. Researchers said the malware typically focuses on rapid collection and exfiltration rather than persistence, stealing browser credentials, cookies, authentication tokens, Apple Keychain data, macOS passwords, and cryptocurrency wallet information from infected systems.
Multiple macOS stealer families have been tied to the tactic, including Atomic macOS Stealer (AMOS), Poseidon, Odyssey, and MacSync. AMOS in particular has been marketed as malware-as-a-service and distributed through malvertising, SEO poisoning, fake download pages, social media ads, GitHub-hosted binaries, open directories, poisoned search results, and piracy forums while impersonating popular apps such as Notion, Trello, Arc, Slack, Todoist, and CleanMyMac X. Defenders were urged to monitor suspicious DMG mount activity in /Volumes, inspect hidden .background directories, use OCR on installer graphics, unmount suspicious disk images quickly, and restrict software installation to legitimate, Apple-verified sources outside unofficial or cracked-software channels.

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CyberProof reported renewed Atomic macOS Stealer activity in financially motivated campaigns using deceptive software downloads, fake websites, and social-engineering lures. The report said AMOS used native macOS tools to steal browser data, the macOS Keychain database, and developer files, then exfiltrated the data via HTTP PUT to bestbuydomain.com with retry and cleanup logic.
Huntress reported that in 2025, more than 65% of newly reported macOS malware was classified as infostealers. The finding reflects a shift toward treating Apple systems as high-value targets for credential and wallet theft.
Sophos states that Atomic macOS Stealer was first reported by Cyble in April 2023. AMOS was described as a macOS infostealer sold via Telegram as malware-as-a-service.
Bitdefender reported a new and largely undetected macOS variant of Atomic Stealer (AMOS) found in malicious DMG files. The company detailed its Python-and-AppleScript theft chain, browser and wallet targeting, C2 endpoint, and said code similarities with RustDoor supported prior attribution of AMOS to a Russian threat actor.
SentinelOne published analysis of Atomic Stealer (AMOS), a macOS infostealer marketed on Telegram for $1,000 per month. The report described multiple variants, AppleScript-based credential theft, targeted browser and wallet data, and related infrastructure and indicators.
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