News that Microsoft had to issue an emergency patch to fix a flaw in all versions of Internet Explorer reminds me how important it is for parents to make sure that all the computers in your household have up-to-date anti-malware software and the latest updates to the operating system.

While Windows PCs seems to attract a lot more attacks than Macs, the Apple Macintosh is not invulnerable to malicious software.  That’s why Apple regularly updates its operating system as does Microsoft — and why some leading security software companies including Symantec and TrendMicro offer Macintosh security software.

The latest threat is a flaw in all versions of Internet Explorer that makes it possible for an attacker to take remote control of your PC, capture user names and passwords and log keystrokes.  All you have to  do to be exposed is to visit an infected ‘Web site, whether it is a site set up by a hacker or even a legitimate site that been injected with the malicious code.  The Associated Press reports that “thousands of Web sites already have been compromised by criminals looking to exploit the flaw.” That’s because the flaw was disclosed about a week before Microsoft issued a fix.

Microsoft was expected to release a fix on Wednesday, December 16, which would be automatically applied to any machine that has automated updates turned on.  To be sure, you can manually scan your computer to see if its security fixes are up-to-date by visiting WindowsUpdate.microsoft.com.  For this particular site, you must use Internet Explorer (other browsers such as Google’s Chrome and Mozilla Firefox works with the vast majority of sites but not this one).Speaking of other browsers, only Internet Explorer is affected by this particular flaw but that doesn’t mean that Firefox and Chrome are exempt from other vulnerabilities.

PC security is a cat-and-mouse game. The good guys are always trying to catch up, but, with billions of dollars of ill-gotten gain at stake, the bad guys are always thinking up something new.

And parents, be sure your kids know not to download anything without your permission  — and don’t you download anything unless you know it’s from a reputable site. Even then, make sure you have a good Internet security suite installed and that it’s up-to-date.