A recent malware campaign has emerged targeting macOS systems, utilizing a technique that leverages extended file attributes to conceal malware. The malware, known as RustyAttr, was uncovered by Singapore-based cybersecurity company Group-IB and has been linked to the North Korean Lazarus Group with moderate confidence. Extended attributes, which allow for additional metadata storage, are being exploited by attackers to smuggle malicious scripts onto targeted devices. This novel approach bypasses traditional detection mechanisms, potentially posing significant risks to macOS users.
The RustyAttr malware is developed using Tauri, a cross-platform framework, and signed with a certificate that has been revoked by Apple since its discovery. Upon execution, the malware runs a shell script embedded within the extended attributes, which triggers a decoy in the form of an error message or a benign PDF related to gaming project funding. This distraction tactic aims to prevent victims from suspecting malicious activity. Additionally, the application attempts to render a fake HTML webpage, loading malicious JavaScript through a Rust backend, further concealing the malware’s presence.
The Lazarus Group, a North Korean-linked cybercriminal organization, has previously been associated with attacks on cryptocurrency companies and global businesses. Although the exact motive behind RustyAttr remains unknown, the campaign appears to involve sophisticated social engineering tactics, as macOS users would need to disable built-in protections like Gatekeeper to activate the malware. The use of revoked certificates and legitimate development frameworks points to a well-resourced and strategic approach, characteristic of Lazarus’s operations in previous campaigns.
Group-IB researchers noted that the Lazarus Group continues to engage in campaigns aiming to compromise organizations worldwide, often by targeting cryptocurrency companies through techniques like remote job applications. RustyAttr exemplifies the advanced methods used by Lazarus to bypass security protocols and gain unauthorized access to sensitive systems. As North Korean threat actors persist in refining their cyber strategies, macOS users are urged to stay vigilant and ensure that system protections remain enabled to mitigate the risk posed by such targeted attacks.
