For years, many have believed that Apple wasn’t under as great a threat of computer viruses compared to Windows, with the original count for Mac viruses being roughly five. Now, though, it seems virus makers are getting the last laugh, with a new trojan out there infecting Mac users who are caught unaware.

If you’re into watching free videos online and you own a Mac, it might be time to keep those eyes aware of what’s happening in the security world, as a new virus seems to be infecting Macs with a way that has been pretty common for Windows computers.

Found by Russian security group Dr. Web and reported by TNW, the infection – which affects users of Chrome, Firefox, and Safari on Mac OS – downloads itself with a so-called install of a program called “Free Twit Tube” when visiting pages where you’re encouraged to check something out, such as movie trailers, online videos, or something to help you surf the internet even faster.

Once installed, the virus inserts itself into pretty much every web page you visit, advertising some products from an ad network and hoping you naturally click on them and spend, spend, spend.

“While Mac computers are fantastic to use and mainly trouble free, when a virus does hit all hell breaks loose and the issue can be more serious than a similar virus on a computer running Windows,” said Wayne Kirby, Product Specialist for Kaspersky Lab in Australia and New Zealand.

These days, it’s more or less a certainty that every computer needs some form of internet security, and while Windows PCs have lived with that requirement for a while, Mac users probably need to know about it more than ever, because virus makers are looking squarely at them.

“Due to the false sense of security Mac users have built up over time with the ‘virus free platform’ myth, users are now more vulnerable than those using the Windows platform,” said Kirby.

“The majority of the attacks are not trying to exploit any weakness in the Mac OS X operating system itself, [but] through social engineering, for example. Mac users can be just as easily be tricked, in some cases more so, than their Windows counterparts into loading false programs or clicking on malicious links.”

It shouldn’t be hard to guess that the results from clicking these links can be pretty catastrophic, so if you’re a Mac user, it’s worth a moment of your time looking into a form of Mac security, just in case you accidentally click on one of these links.