Malware coders have created a Mac-specific Trojan that is designed to attack anti-malware defences built into Apple's Mac OS X operating system.

The Flashback.C trojan disables the automatic update component of XProtect, OS X's anti-malware application, net security firm F-Secure reports. By wiping out files, the malware prevents future updates, making it more likely that the devilish code will be able to stick around for longer.

The approach mimics a tactic long seen in the world of Windows malware, where attempts to disable security software have been commonplace for years as well as illustrating the growing sophistication of crooks targeting Macs with malware.

"Attempting to disable system defences is a very common tactic for malware — and built-in defences are naturally going to be the first target on any computing platform," F-Secure notes.

The Flashback.C Trojan poses as a Flash Player installer. In reality, the malware sets up a backdoor connection to a remote host. Although currently inactive, the remote host linked to the malware might be used to push any manner of crud onto infected machines.

Previous versions of the Flashback Trojan shunned virtual machines, a technique designed specifically to frustrate anti-virus analysis.