A U.S. security firm has found that iPhone and iPad users in China are facing the threat of a new virus that attacks their mobile devices via Mac desktop and laptop computers.

The virus jumps from Mac OS X to the mobile device via a USB cable, says Palo Alto Networks, the U.S. firm that discovered the threat. That’s why firm’s engineers dubbed the virus ‘WireLurker.’

“WireLurker monitors any iOS device connected via USB with an infected OS X computer and installs downloaded third-party applications or automatically generated malicious applications onto the device, regardless of whether it is jailbroken,” Palo Alto Networks’ Claud Xiao writes at the firm’s blog.

The malicious code is believed to hide inside apps that users download from third-party Mac OS X app stores. It then infects other apps already running on the user’s desktop or laptop computer, Palo Alto Networks says.

“WireLurker was used to trojanize 467 OS X applications on the Maiyadi App Store, a third-party Mac application store in China,” Xiao writes in the blog. “In the past six months, these 467 infected applications were downloaded over 356,104 times and may have impacted hundreds of thousands of users.”

Palo Alto Networks says this type of threat is nothing new, but it’s the first time it’s been used to target Apple machines specifically.

It’s also of concern because while previous viruses threatened only jailbroken devices, WireLurker can infiltrate non-jailbroken devices, too. Users sometimes jailbreak their phones so that they can install apps that Apple has not approved.

Hat tip: CNET