Miscreants are coining it by infecting fanbois beloved Apple boxes with a well-known ad-injecting Trojan previously only found on Windows machines.

Trojan.Yontoo.1, the specially crafted Mac OS X version, penetrates computers running OS X by offering what purports to be a browser plugin necessary to view content, but is actually adware.

Once users have installed the plugin, the Trojan is downloaded onto the Apple machine, where it quickly installs the adware into Chrome, Firefox and Safari. Cybercrooks profit from the malware by tapping into affiliate ad network programmes.

To spread Yontoo, the VXers have set up fake movie trailer pages that prompt users to install a browser plugin supposedly need to view content - actually Yontoo-1. The Trojan also poses as a media player, a video quality enhancement program or a download accelerator.

The threat was detected by Russian software security firm Doctor Web, which describes it as part of a Mac-specific adware problem that has been growing since the start of 2013.

Windows adware has been a problem for years. ®