The acquisition increases Microsoft’s presence as an anti-virus and anti-spam technology provider, but the selection of East Northport, New York-based Sybari indicates that Microsoft is looking to protect its relationships with other anti-virus specialists.

Sybari is somewhat unusual as an anti-virus vendor in that it does not create its own virus definitions or scanning engines but enables customers choose multiple anti-virus packages from partners including Sophos, Computer Associates, Kaspersky Labs, VirusBuster and Norman.

The idea is that anti-virus firms are unpredictable in their response times to new malware outbreaks and companies can manage their risk more effectively by having two or more scanners, with Sybari’s Antigen tying them together.

In announcing the deal, Mike Nash, corporate vice president of Microsoft’s security business and technology unit, praised Sybari’s use of multiple scan engines, a strategy that provides increased virus cover for customers and will enable Microsoft to keep its distance from virus definition.

The role of Microsoft in the anti-virus market has been the subject of much debate since it acquired Romanian anti-virus firm GeCad Software in June 2003. The first fruit of that acquisition, Microsoft’s Malicious Software Removal Tool, was released in January, but is an anti-virus cleanup tool, rather than a full-blown anti-virus offering.

The company has previously stated that will come later this year, but details are thin on the ground, along with information about how Microsoft proposes to package the GeCad and Sybari technologies.

A Microsoft spokesperson told ComputerWire that the company will continue to work closely with partners, including Sybari’s existing scan engine partners, but will offer the GeCad engine as one of the anti-virus engines available to license with Antigen.

Sybari’s product include the Antigen anti-virus products for Microsoft Exchange, Microsoft SharePoint, Microsoft Live Communications Server, Lotus Domino, and SMTP Gateways, as well as well as the server-based Antispam and Content Filtering, which works with its Antigen for Exchange and SMTP Gateways.

Microsoft’s spokesperson added that the company would continue to provide support for Sybari’s entire product line across all platforms.

Microsoft said it has been using Sybari’s anti-virus technology internally since May 2004, the same month that Sybari filed for an initial public offering from which it hoped to raise $61.6m.

Ironically, Microsoft potential to compete in the anti-virus space was listed as one of the biggest risks for Sybari in its filing with the Securities and Exchange Commission, which also revealed that 95% of its revenue comes from products designed to protect Microsoft collaboration server and instant messaging environments.

According to the filing, Sybari recorded a net loss of $1.0m on revenue of $34.1m in the first nine months of 2004. That followed a net loss of $400,000 in full year 2003 on revenue of $38.3m, an improvement on a net loss of $2.m on revenue of $30.9m in 2002.