Just when you thought it was safe to go back into your email inbox .

I know many of us don't feel like our email inboxes are all that safe, considering that the villains who write viruses and worms are getting more and more adept at finding ways to trick us. One dirty trick cropping up lately is a new virus that comes in an email message, claiming to be a beta of Microsoft's (NASDAQ:MSFT) MSN Messenger product.

Among the major Internet companies, beta tests of new and upcoming products have been all the rage over the last couple of years. One prominent example that springs to mind for me is how Google (NASDAQ:GOOG) gave its Gmail launch in 2004 a downright exclusive feel by allowing only a limited amount of individuals to test-drive it at first and relying on invitation-only (read: viral) means to spread the new product.

Unfortunately, it seems that maybe hackers and virus writers figured out that a beta test can feel like a special privilege. And for some people, that's a tempting hook.

According to CNET, the virus is called Virkel.F, and it's sent out in email form. Victims who click on a link are taken to a website where a file called "BETA8WEBINSTALL.EXE" can be downloaded. It's not a beta of the "MSN Messenger 8" product (which doesn't actually exist at all), as it claims to be, but once installed, it sends download links to everyone in a user's MSN Messenger buddy list. The company that publicized the virus, F-Secure, also said that it connects victims' machines to something called a "botnet server." Much like many viruses and worms, that means that the user's PC can be used like a zombie machine, attacking other machines or sending out loads of spam.

Attacks on IM programs are on the rise, and although MSN Messenger is not the top instant-messaging software -- Time Warner's (NYSE:TWX) AOL has the most popular IM product, AIM -- the CNET article pointed out that one research group found that MSN Messenger has been used quite frequently for such IM viruses.

Making matters more complex, Microsoft does have a new version of its IM software with all the latest features that is being beta tested by a select group of individuals -- but it's called Windows Live Messenger, not MSN Messenger 8.

The more technology expands, the more hackers try to wreak havoc. It's pervasive -- worms and viruses have been known to infect users' machines from websites, email spam, and IM spam (aka spim), and even through cell phones. Most of us know by now that we need to cast a skeptical eye toward the messages we receive.

A Techworld article said that a Microsoft spokeswoman did acknowledge the malicious threat and cautioned users against downloading anything from any sites other than those affiliated with Microsoft or MSN in news articles, although I was a bit surprised not to see a prominent message concerning this possible threat on the MSN Virus & Security page. Although companies like Microsoft and Yahoo! (NASDAQ:YHOO) are dying to take out AIM's dominance in wildly popular instant messaging, poor handling of security threats could certainly pose a roadblock to their success.

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Alyce Lomax does not own shares of any of the companies mentioned.