Researchers at Russian security company Doctor Web are warning of a new Mac Trojan called Trojan.SMSSend.3666, which poses as legitimate software.

"As with all Trojans, these pose as legitimate programs that are made available for download from a number of underground Web sites, with this current one for OS X appearing to be an installer for a program called VKMusic 4, a utility whose legitimate version is used for communication between machines on a European social network called VK," writes CNET News' Topher Kessler.

"When a user launches the fake installer on OS X, he or she is presented with an interface that imitates the installation wizard of a corresponding application," writes The Next Web's Emil Protalinski. "In order to continue the 'installation process,' the user is prompted to enter their cellphone number into the corresponding field and then input a code they are to receive via SMS. By doing so, the user is charged a subscription fee debited to their mobile phone account on a regular basis."

"Doctor Web says the text-message scam installer isn’t new," writes Forbes' Andy Greenberg. "But it’s only recently been converted to target Mac users, the first such scam of its kind to hit Apple’s relatively malware-free operating system."

"The vast majority of malware, Trojans and other malicious bugs are meant to run on Windows machines and therefore often aren't a threat to Macs," notes TechNewsDaily's Ben Weitzenkorn. "But as Apple continues to increase its market share, security experts have predicted the end of Apple customers' happy days very soon."