A new family of malware on Mac computers has been discovered, and it could be infecting iPhones too.

A team of security researchers at Palo Alto Networks has found that WireLurker, a family of malware is targeting Macs and iPhones. While currently only affecting the Chinese market, the malware has been entering the user’s computer via a third party Mac application store in China called Maiyadi.

The malware can then go on to infect iPhones via a USB cable.

The findings were revealed in a research paper, which explains how the malware works. It says that it’s been distributed through ‘trojanized’ or repackaged OS X applications in what Palo Alto describes as “the biggest in scale we have ever seen” and is only the second known malware family that attacks iOS devices through OS X via USB.

The report goes on to reveal that 467 OS X applications in the Maiyadi App Store were trojanized by WireLurker which have been downloaded over 356,104 times in the last 6 months, potentially affecting hundreds of thousands of users.

While it’s much more common for iPhones to be infected by malware when they are jailbroken – the process of removing the limitations Apple places on its iOS – this family infects non-jailbroken iPhones. It does this by sitting on a user’s Mac, waiting for a USB connection. As soon as the iPhone is plugged in, it infects the device, apparently gaining access to all user data.

Palo Alto has said that so far the malware hasn’t been used to exploit any data, or devices, but that it could be readying for a later attack. Apple, meanwhile, are patching the vulnerability, and alongside it being locale-specific, the majority of iPhone users won’t need to worry too much about the problem.