If you're worried about hackers and cybercriminals, but you think you're safe because you've got a Mac, you need to change your thinking fast. Macs are no longer the invulnerable devices they once were.

Years ago, Macs were remarkably safe, compared to Windows PCs. Part of the reason for that is hackers didn't spend much time attacking them because they were relatively unpopular.

That has changed. In fact, Macs are one of the few bright spots in the PC marketplace. While overall PC sales were down 7.7 percent from third quarter last year, according to Gartner, Mac sales were up 1.5 percent, and rank as the No. 4 computer brand.

Hackers have been having a field day with Macs for at least the past year. We've been telling you a lot about malware attacks on Mac computers. Yet, it's even worse than we thought. This is shocking news and you have to take action now.

So far in 2015, there have been 948 types of malware found on Apple's OS X operating system. That's five times as many types of malware than were found in Macs in the prior five years combined.

Researchers from Bit9 + Carbon Black spent 10 weeks tracking down Mac malware. Their findings are disheartening, especially for loyal Apple users.

However, there is good news here. Bit9 + Carbon Black also found that, generally speaking, Mac hackers aren't a sophisticated lot. They tend to use just seven methods to get into Macs: LaunchAgents, LaunchDaemons, cron jobs, login items, browser plug-ins, StartUpItems, and binary infections.

Even better, most attacks involved just one of these methods. Bit9 + Carbon Black didn't say which one.

The big point is that while Mac malware attacks are on the rise, they are relatively easy to prevent with anti-virus software. If you've got a Mac, it's more important than ever to keep your computer protected. Do it now before it's too late.

On the Kim Komando Show, the nation's largest weekend radio talk show, Kim takes calls and dispenses advice on today's digital lifestyle, from smartphones and tablets to online privacy and data hacks. For her daily tips, free newsletters and more, visit her website at Komando.com. Kim also posts breaking tech news 24/7 atNews.Komando.com