Cybersecurity analysts have detected a sophisticated malware sample that attacks Apple users in the wild. The joint research from Red Canary, Malwarebytes, and VMWare Carbon Black details that approximately 30,000 hosts across 153 countries have been compromised by the new threat dubbed Silver Sparrow. The topmost infection rates were spotted in the United States, Canada, France, the United Kingdom, and Germany.
Currently, the Silver Sparrow’s delivery methods remain unknown, and what is even more interesting, the final goal of the malicious activity is still undetermined. However, security professionals point to the sophistication of the new threat due to its ability to target new Apple M1 chips, novel evasion tactics, and unusual malicious behavior.
As for February 2021, security analysts uncovered two existing variants of Silver Sparrow delivered under updater.pkg and updater.pkg file names. Both strains are similar in functionality, the only distinction is that updater.pkg contains a Mach-O binary supporting both Intel x86_64 and M1 ARM64 architectures, while updater.pkg supports Intel x86_64 architecture exclusively.
Apart from the final goal puzzle, Silver Sparrow performs an unusual file check. Particularly, the malware checks for the ~/Library/._insu presence on disk, and if identified, Silver Sparrow deletes all its files from the system. The purpose of this check currently remains unknown.
Another indication of Silver Sparrow’s sophistication is the fact that it is compatible with macOS systems running Apple’s latest M1 chip. It is the second threat ever detected to support M1 ARM64 architectures. Such an innovation significantly complicates the static analysis and lowers the detection rate for this malicious strain by antivirus solutions.
On February 22, 2021, Apple revoked the certificates leveraged by Silver Sparrow creators to sign the installation packages. This way the vendor protects its users from further malware propagation and blocks any new infections.
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