Over the past couple of years, Microsoft has made a sincere effort to address the gaping security issues surrounding their products. While newer versions of their software, including Exchange 2003 (when used in combination with Outlook 2003), are better than old versions when it comes to security, Exchange security is still considered a moving target when it comes to spam, worms, and viruses. In 2005, Microsoft acquired a company called Sybari and, in July of 2006, released the first Microsoft-branded products to come out of this purchase.
Named Microsoft Antigen, this new line of products is designed to protect servers running Exchange, SharePoint and Live Communications Server. The July 2006 release includes Microsoft Antigen for Exchange, Microsoft Antigen for SMTP Gateways, Microsoft Antigen Spam Manager, and Microsoft Antigen Enterprise Manager.
Antigen provides another security layer that helps you to prevent spam, worms, viruses, and inappropriate content from making its ways into your mail system. Antigen is capable of running with multiple scanning engines to provide a better level of security. For example, Microsoft Antigen for Exchange can use Microsoft's scanning engine, plus a scanning engine from Sophos. Multiple scanning engines help you to detect and eradicate threats more quickly.
For more information on Antigen, or to register for a free trial, visit Microsoft's Antigen page.