Mac users have been forced to face a cold reality lately\u00a0--\u00a0the days of security through obscurity are over. Macs have traditionally been off the radar, and relatively safe just by virtue of being Macs. Now that malicious attacks are targeting Macs, users need to defend themselves. Avast is stepping up to offer its popular free antimalware software for Mac OS X.No, malware is nowhere near the scourge for Mac OS X as it is for Windows. I am not saying the "sky is falling", and I'm not declaring a "Macpocalypse". But, the reality is that malicious attacks exist, and the threat will continue to grow. Macs have been gaining in market share, and the growth rate of Mac is outpacing the growth rate for Windows-based PCs, so the operating system has captured the attention of malicious developers. It's time to recognize that, and implement security tools to defend against attacks.Even if you truly believe that malware is just not an issue for you on a Mac, there's still good reason to use security software. A recent report found that many Macs are like the "Typhoid Mary" of the Internet. One in five Mac systems was found to be carrying malware that has no impact on Mac OS X, but can still be shared and pose a risk to Windows PCs.Thankfully, protecting your Mac doesn't have to cost you a penny. Avast announced today that it now offers a version of its popular antimalware and security software for Mac OS X.An Avast press release explains, "The new app provides Mac users with three defensive shields: the Web and Mail Shields for incoming data and the File Shield to scan the user's hard drive."Avast uses avast! CommunityIQ--a user-based sensor network--to collect data and detect new threats in real time. The constant stream of new threat data enables Avast to identify new threats and quickly issue updates for emerging threats to protect users.For Mac users, phishing attacks and other social engineering threats are probably a bigger threat than the traditional malware that affects Windows PCs. Mac users lack the cautious skepticism and security conditioning Windows users have, and are generally more likely to click on a link to a malicious site or share sensitive data. Avast WebRep is an anti-phishing and Web reputation plug-in that uses information from avast! CommunityIQ to detect and block suspected phishing sites.You may not think you need it, but you do--and the price is right. Give the free Avast for Mac software a try.