Microsoft is currently alpha-testing its upcoming antivirus product, according to industry sources Computerworld has spoken to.

The sources claim that the antivirus software works as a "behavior blocker" that monitors different events and actions on computers. If the event or action is typical of virus or is harmful, it will be prevented.

Behavior blockers do not use code signatures like traditional scanner-based antivirus programs, so they may be able to protect against new types of viruses without being updated -- an important consideration for Microsoft.

The antivirus product was also referred to as an Intrusion Detection and Protection System by sources, indicating that it may work in conjunction with the Windows Firewall.

An interesting feature of Microsoft's antivirus software is that it is distributed, according to the sources. It communicates with other machines over a secure channel and learns from these. More details on this capability was not available as Computerworld Online was published.

Alpha-quality software is not yet ready for release; it is typically not feature-complete and may still have significant bugs.

Earlier press reports quoted Microsoft's technical head of security in France, Nicolas Mirail, as having shared details of the new program. According to Mirail, the program will reference a regularly updated list of known viruses to check for infections. It will also analyze computers to see if they have been infected by viruses in the past, and attempt to advise users on how big a risk they stand in the future.

In 2003, Microsoft bought Romanian antivirus vendor GeCAD and Pelican Security Software, which makes behavior blocking software. Technology from both companies will be incorporated in the new antivirus product. The release date is not yet known.

Microsoft New Zealand's communications manager, Carol Leishman, declined to comment on specific details about the new antivirus offering, but confirmed that a product was in the works. "When we bought GeCAD last year, Microsoft said it would provide (antivirus) services and engines," she says.

Leishman says a Microsoft study revealed that around 63 percent of users either didn't have an anti-virus installed, or didn't keep installed ones up-to-date. Hinting that behavior blocking is indeed built into the new AV product, Leishmann says it will have "sandboxing that protects the system before infection".