Security researchers have discovered a proof-of-concept code for an adware program that targets Apple's OS X operating system.
According to analysts at F-Secure the program - named iAdware - installs itself through a feature in the operating system that allows system libraries to be installed, but doesn't require user permission to do so.
"We won't disclose the exact technique used here, it's a feature not a bug, but lets just say that installing a system library shouldn't be allowed without prompting the user," F-Secure said in a blog on its website. "Especially as it only requires copy permissions. An administrator could install this globally to all users," it continued.
The Finland based company tested the proof-of-concept and found that it automatically launches a browser window each time the user opened an application. This could be used by hackers to bombard people with unwanted pop-up advertisements based on data gathered from the adware.
Mikko Hypponen, chief research officer at F-Secure said while criminals continue to target Windows users, the Mac is becoming an increasingly attractive target for hackers.
"This proof-of-concept example was made by a known security researcher to highlight Mac vulnerabilities but, other malicious parties may be interested in exploiting it," he said.
"We have yet to see adware and spyware that targets the Mac for financial gain. But, the Mac is not 100 per cent safe, sooner or later we will see adware that targets Mac users. We have already seen viruses. Nevertheless, in practice you are still more secure using a Mac online - at the moment," he added.
This posting from F-Secure comes at a time when several other pieces of proof-of-concept code have been released questioning the view that Apple's operating system is less vulnerable to malware attacks.
According to David Frazer, director of technology services at F-Secure, because this latest program installs onto the computer without permission this could lead to an increase in silent hacking attacks.
"For a long time now Mac users have had the feeling that malware is only going to the PC market. This could potentially open the risk for scams that Mac users never see," he said.
Apple did not return requests for comment.