Microsoft's latest move into the antivirus and anti-spam markets became known today with plans announced to purchase Sybari Software, whose products reportedly protect over 10,000 businesses.

In June 2003 Microsoft also acquired anti-virus maker GeCAD and in December 2004 Microsoft acquired anti-spyware maker GIANT Software.

The Sybari acquisition will allow Microsoft to offer technology that can help protect against malware and filter spam at the server level on many platforms including multiple versions of Lotus Notes, Exchange Server, SMTP gateways, SharePoint Portal Server, Windows SharePoint Sevices, and Live Communications Server.  For the time being Microsoft will continue to offer Sybari solutions under their original banner.

Microsoft said that it tested several gateway-level anti-virus solutions over the last year. The company did not say which solutions it tested, however it's probably safe to assume that it looked closely at those solutions that were likely to be available for acquisition. Out of the products tested the company found Sybari to be the best choice for its needs, which led to the subsequent purchase of the company.

Terms of the deal have not been made public. However, Australian IT reports that Sybari values itself at somewhere between $163 million and $182 million dollars.