12.338.2004 - E-mail messages that contain a virus remain in the SMTP local delivery queue after you configure Intelligent Message Filter in Exchange Server 2003 (KB883522)

After you install and configure Microsoft Exchange Intelligent Message Filter on your Microsoft Exchange Server 2003 computer, e-mail messages that contain a computer virus or a worm program are not permanently deleted. Instead, these e-mail messages remain in the SMTP local delivery queue in Exchange 2003 until they time out. - Download Exchange Server 2003 update - View Microsoft Knowledge Base Article - 883522 - Visit Microsoft Corporation