You should follow the best practice recommendations in the Windows Server 2008 Security Guide,for hardening your W2K8 VMs. The GPO Accelerator can make this easier. The GPOAccelerator creates all the Group Policy objects (GPOs) that you need to deploy recommended security settings for your environment to save you hours of work that you would otherwise need to configure these settings.
BTW, the guide was published before Hyper-V RTM. When the Security Guide is updated, a new worksheet in the Attack Surface Reference Workbook will be added that lists the attack surfaces for Hyper-V. Until then, you can find the same information in the Hyper-V Attack Surface Reference Workbook, available for download today at http://download.microsoft.com/download/8/2/9/829bee7b-821b-4c4c-8297-13762aa5c3e4/Windows Server 2008 Hyper-V Attack Surface Reference.xlsx. Copy=-paste into your Attack Surface Reference Workbook from the Security Guide and you are good to go.
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