We often use Security Advisories to let you know when we’re aware of security incidents that can affect customers. We also use Security Advisories to let you know about important information that can relate to your overall security. In this case, we’re letting you know about two non-security updates that we think it’s important for you to review.

The first advisory is Microsoft Security Advisory (927891). This advisory is to let you know about an update to the Windows Installer, sometimes called the MSI installer. This update applies to currently supported versions of Windows except Windows Vista. The update addresses an issue you may experience where systems may become unresponsive when Windows Update or Microsoft update is scanning them. This update is being released through Windows Update, Microsoft Update and Automatic Updates. I want to note that this update will install correctly even if you’re experiencing this issue. However, the issue may prevent you from installing other updates (including security updates) until you apply this new update, so we encourage customers to apply this right away.

The second advisory is Microsoft Security Advisory (937696). This advisory announces the availability of the Microsoft Office Isolated Conversion Environment (MOICE) feature. It also lets you know more widely of the ability to restrict opening or saving types of files in Microsoft Office 2003 and the 2007 Microsoft Office system (called "file block" by some). In the 2007 Microsoft Office system, this capability is part of the 2007 Office System Administrative Templates. For Office 2003, this capability is included in MS07-023 for Excel, MS07-024 for Word, and non-security update 933669 for PowerPoint.

The MOICE tool works to help protect you from malicious Office documents by capturing the legacy file format associations and diverting file open requests to this new process. First, it converts the document to the new Office Open XML format. It then converts back to the legacy binary format before handing off to the regular Office application to open the document. As David discussed in detail, this conversion happens in an isolated, low-rights environment which helps protect against attempts to exploit the conversion.