Apple devices are at risk of a virus described by researchers as 'the biggest scale' malware they have ever seen.
Dubbed WireLurker, the malware targets both Mac computers as well as phones and tablets running iOS when connected using a USB cable.
After it has infected the Mac, when a mobile device is connected to the infected computer the virus spreads and installs malicious apps.
HOW WIRELURKER WORKS
WireLurker monitors iOS devices, including iPods, iPhones and iPads, connected to a Mac via USB.
The virus begins by infecting the Mac OS software, through malicious files or links.
When a device is connected to this infected Mac, the malware automatically installs malicious apps onto the phone or tablet.
The researchers said this malware combines a number of techniques to successfully 'realise a new brand of threat to all iOS devices'.
The experts suggest iOS and Mac owners only download apps from the official Apple app store, and that they make sure to keep their software up to date.