Microsoft Office System 2010 Security Technical Implementation Guide

Having access to updates, add-ins, and patches on the Office Online Web site can help users ensure computers are up to date and equipped with the latest security patches. However, to ensure updates are tested and applied in a consistent manner, many organizations prefer to roll out updates using a centralized mechanism such as Microsoft Systems Center or Windows Server Update Services. By default, users are allowed to download updates, add-ins, and patches from the Office Online Web site to keep their Office applications running smoothly and securely. If your organization has policies that govern the use of external resources such as Office Online, allowing users to download updates might cause them to violate these policies.

Office users can share Excel, PowerPoint, and Word templates they create with other Microsoft Office users around the world by uploading them to the community area of the Microsoft Office Online Web site. If your organization has policies that govern the use of external resources such as Office Online, allowing users to upload templates might enable them to violate those policies.

Office document on a Web server using Internet Explorer, the appropriate application opens the file in read-only mode. However, if the default configuration is changed, the document is opened as read/write. Users could potentially make changes to documents and resave them in situations where the Web server security is not configured to prevent such changes.

When saving documents as Web pages, Excel, PowerPoint, and Word can save vector-based graphics in Vector Markup Language (VML), which enables Internet Explorer to display them smoothly at any resolution. By default, when saving VML graphics, Office applications also save copies of the graphics in a standard raster file format (GIF or PNG) for use by browsers that cannot display VML. If the Rely on VML for displaying graphics in browsers check box in the Web Options dialog box is selected, applications will not save raster copies of VML graphics, which means those graphics will not display in non-Microsoft browsers.

The Help Improve Proofing Tools feature collects data about use of the Proofing Tools, such as additions to the custom dictionary, and sends it to Microsoft. After about six months, the feature stops sending data to Microsoft and deletes the data collection file from the user's computer. Although this feature does not intentionally collect personal information, some of the content sent could include items that were marked as spelling or grammar errors, such as proper names and account numbers. However, any numbers such as account numbers, street addresses, and phone numbers are converted to zeroes when the data is collected. Microsoft uses this information solely to improve the effectiveness of the Office Proofing Tools, not to identify users. By default, this feature is enabled, if users choose to participate in the Customer Experience Improvement Program (CEIP). If your organization has policies that govern the use of external resources such as the CEIP, allowing the use of the Help Improve Proofing Tools feature might cause them to violate these policies.

The Opt-in Wizard displays the first time users run a 2010 Microsoft Office application, which allows them to opt into Internet-based services that will help improve their Office experience, such as Microsoft Update, the Customer Experience Improvement Program, Office Diagnostics, and Online Help. If your organization has policies that govern the use of such external resources, allowing users to opt in to these services might cause them to violate the policies.

When users choose to participate in the Customer Experience Improvement Program (CEIP), Office applications automatically send information to Microsoft about how the applications are used. This information is combined with other CEIP data to help Microsoft solve problems and to improve the products and features customers use most often. This feature does not collect users' names, addresses, or any other identifying information except the IP address that is used to send the data. By default, users have the opportunity to opt into participation in the CEIP the first time they run an Office application. If your organization has policies that govern the use of external resources such as the CEIP, allowing users to opt in to the program might cause them to violate these policies.

Office Diagnostics is used to improve the user experience by periodically downloading a small file to the computer with updated help information about specific problems. If Office Diagnostics is enabled, it collects information about specific errors and the IP address of the computer. When new help information is available, that help information is downloaded to the computer that experienced the related problems. Office Diagnostics does not transmit any personally identifiable information to Microsoft other than the IP address of the computer requesting the update. By default, users have the opportunity to opt into receiving updates from Office Diagnostics the first time they run a 2010 Office application. If your organization has policies that govern the use of external resources such as Office Diagnostics, allowing users to opt in to this feature might cause them to violate these policies.

The Message Bar in Office applications is used to identify security issues, such as unsigned macros or potentially unsafe add-ins. When such issues are detected, the application disables the unsafe feature or content and displays the Message Bar at the top of the active window. The Message Bar informs the users about the nature of the security issue and, in some cases, provides the users with an option to enable the potentially unsafe feature or content, which could harm the user's computer. By default, if an Office application detects a security issue, the Message Bar is displayed. However, this configuration can be modified by users in the Trust Center.

When Information Rights Management (IRM) is used to restrict access to an Office Open XML document, any metadata associated with the document is not encrypted. This configuration could allow potentially sensitive information such as the document author and hyperlink references to be exposed to unauthorized people.

When an Office Open XML document is protected with a password and saved, any metadata associated with the document is encrypted along with the rest of the document's contents. If this configuration is changed, potentially sensitive information such as the document author and hyperlink references could be exposed to unauthorized people.

If unencrypted files are intercepted, sensitive information in the files can be compromised. To protect information confidentiality, Office application files can be encrypted and password protected. Only users who know the correct password will be able to decrypt such files.

If unencrypted files are intercepted, sensitive information in the files can be compromised. To protect information confidentiality, Microsoft Office application files can be encrypted and password protected. Only users who know the correct password will be able to decrypt such files.

ActiveX controls can adversely affect a computer directly. In addition, malicious code can be used to compromise an ActiveX control and attack a computer. To indicate the safety of an ActiveX control, developers can denote them as Safe For Initialization (SFI). SFI indicates a control is safe to open and run, and it is not capable of causing a problem for any computer, regardless of whether it has persisted data values or not. If a control is not marked SFI, it is possible the control could adversely affect a computer-or it could mean the developers did not test the control in all situations and are not sure whether it might be compromised in the future. By default, if a control is marked SFI, the application loads the control in safe mode and uses persisted values (if any). If the control is not marked SFI, the application loads the control in unsafe mode with persisted values (if any), or uses the default (first-time initialization) settings. In both situations, the Message Bar informs users the controls have been disabled and prompts them to respond.

ActiveX controls are Component Object Model (COM) objects and have unrestricted access to users' computers. ActiveX controls can access the local file system and change the registry settings of the operating system. If a malicious user repurposes an ActiveX control to take over a user's computer, the effect could be significant. To help improve security, ActiveX developers can mark controls as Safe For Initialization (SFI), which means that the developer states that the controls are safe to open and run and not capable of causing harm to any computers. If a control is not marked SFI, the control could adversely affect a computer-or it's possible the developers did not test the control in all situations and are not sure whether their control might be compromised at some future date. SFI controls run in safe mode, which limits their access to the computer. For example, a worksheet control can both read and write files when it is in unsafe mode, but perhaps only read from files when it is in safe mode. This functionality allows the control to be used in very powerful ways when safety wasn't important, but the control would still be safe for use in a Web page. If a control is not marked as SFI, it is marked Unsafe For Initialization (UFI), which means that it is capable of affecting a user's computer. If UFI ActiveX controls are loaded, they are always loaded in unsafe mode.

When a separate program is used to launch Microsoft Office Excel, PowerPoint, or Word programmatically, any macros can run in the programmatically opened application without being blocked. This functionality could allow an attacker to use automation to run malicious code in Excel, PowerPoint, or Word.

Unsafe hyperlinks are links that might pose a security risk if users click them. Clicking an unsafe link could compromise the security of sensitive information or harm the computer. Links that Office considers unsafe include links to executable files, TIFF files, and Microsoft Document Imaging (MDI) files. Other unsafe links are those using protocols considered to be unsafe, including msn, nntp, mms, outlook, and stssync.

If 2010 Office users add passwords to documents, other users can be prevented from opening the documents. This capability can provide an extra level of protection to documents already protected by access control lists, or provide a means of securing documents not protected by file-level security. By default, users can add passwords to Excel 2010 workbooks, PowerPoint 2010 presentations, and Word 2010 documents from the Save or Save As dialog box by clicking Tools, clicking General Options, and entering appropriate passwords to open or modify the documents. If this configuration is changed, users will not be able to enter passwords in the General Options dialog box, which means they will not be able to password protect documents.

When Microsoft Office files are opened from trusted locations, all the content in the files is enabled and active. Users are not notified about any potential risks that might be contained in the files, such as unsigned macros, ActiveX controls, or links to content on the Internet. By default, users can specify any location as a trusted location, and a computer can have a combination of user-created, OCT-created, and Group Policy-created trusted locations.

An XML expansion pack is the group of files that constitutes a Smart Document in Excel and Word. You package one or more components that provide the logic needed for a Smart Document by using an XML expansion pack. These components can include any type of file, including XML schemas, Extensible Stylesheet Language Transforms (XSLTs), dynamic-link libraries (DLLs), and image files, as well as additional XML files, HTML files, Word files, Excel files, and text files. The key component to building an XML expansion pack is creating an XML expansion pack manifest file. By creating this file, you specify the locations of all files that make up the XML expansion pack, as well as information that instructs 2007 Office how to set up the files for your Smart Document. The XML expansion pack can also contain information about how to set up some files, such as how to install and register a COM object required by the XML expansion pack. XML expansion packs can be used to initialize and load malicious code, which might affect the stability of a computer and lead to data loss. Office applications can load an XML expansion pack manifest file with a Smart Document.

Excel, PowerPoint, and Word users can use the Internet Fax feature to send documents to fax recipients through an Internet fax service provider. If your organization has policies that govern the time, place, or manner in which faxes are sent, this feature could help users evade those policies. By default, Office users can use the Internet Fax feature.

This setting controls whether Office 2010 users can change permissions for content that is protected with Information Rights Management (IRM). The Information Rights Management feature of Office 2010 allows individuals and administrators to specify access permissions to Word documents, Excel workbooks, PowerPoint presentations, InfoPath templates and forms, and Outlook e-mail messages. This functionality helps prevent sensitive information from being printed, forwarded, or copied by unauthorized people.

The Windows Rights Management Add-on for Internet Explorer provides a way for users who do not use the 2010 Office release to view, but not alter, files with restricted permissions. By default, IRM-enabled files are saved in a format that cannot be viewed by using the Windows Rights Management Add-on. If this setting is enabled, an embedded rights-managed HTML version of the content is saved with each IRM-enabled file, which can be viewed in Internet Explorer using the add-on. This configuration increases the size of rights-managed files, in some cases significantly.

Users are not required to connect to the network to verify permissions. If users do not need their licenses confirmed when attempting to open Office documents, they might be able to access documents after their licenses have been revoked. Also, it is not possible to log the usage of files with restricted permissions if users' licenses are not confirmed.

This controls whether users can open protected content created with a Windows Live ID (formerly Microsoft .NET Passport) authenticated account. If your organization has policies that govern access to external services such as Windows Live ID, this capability could allow users to violate those policies.

Office applications use the XML-based XMLDSIG format to attach digital signatures to documents, including Office 97-2003 binary documents. XMLDSIG signatures are not recognized by Office 2003 applications or previous versions. If an Office user opens an Excel, PowerPoint, or Word binary document with an XMLDSIG signature attached, the signature will be lost.

Users can select Add Signature Services (from the Signature Line drop-down menu on the Insert tab of the Ribbon in Excel 2010, PowerPoint 2010, and Word 2010) to see a list of signature service providers on the Microsoft Office Web site. If your organization has policies that govern the use of external resources such as signature providers or Office Marketplace, allowing users to access the Add Signature Services menu item might enable them to violate those policies.

If the Microsoft Save as PDF or XPS Add-in for Microsoft Office Programs add-in is installed, document properties are saved as metadata when users save files using the PDF or XPS or Publish as PDF or XPS commands in Access 2010, Excel 2010, InfoPath 2010, PowerPoint 2010, and Word 2010, unless the Document properties option is unchecked in the Options dialog box. If this metadata contains sensitive information, saving it with the file could compromise security.

For controlling whether users see a security warning when they open custom Document Information Panels that contain a Web beaconing threat. Web beacons can be used to contact an external server when users open forms. Information could be gathered by the form, or information entered by users could be sent to an external server and cause them to be vulnerable to additional attacks.

Users of Office applications can see and use links to Microsoft Office SharePoint Server sites from those applications. Administrators configure published links to Office applications during initial deployment, and can add or change links as part of regular operations. These links appear on the My SharePoint Sites tab of the Open, Save, and Save As dialog boxes when opening and saving documents from these applications. Links can be targeted so that they only appear to users who are members of particular audiences. If a malicious person gains access to the list of published links, they could modify the links to point to unapproved sites, which could make sensitive data vulnerable to exposure.

The blogging feature in Office products enables users to compose blog entries and post them to their blogs directly from Office, without using any additional software. By default, users can post blog entries to any compatible blogging service provider, including Windows Live Spaces, Blogger, a SharePoint or Community Server site, and others. If your organization has policies that govern the posting of blog entries, allowing users to access the blogging feature in Office might enable them to violate those policies.

This setting controls whether users can follow hyperlinks to templates on Office.com from within Office 2010 applications.

This setting controls the exposing of entry points for Office Live Workspace Integration features.

This policy setting allows you to filter a list of digital certificates for signing Excel, PowerPoint, and Word documents, based on the Key Usage field. The Key Usage field in a certificate is used to represent a series of basic constraints about the broad types of operations that can be performed with the certificate. Key usage filtering allows you to filter the list of installed certificates that can be used for signing documents. The filtered list will appear when users attempt to select a certificate for digitally signing a document.

This policy setting controls whether Office 2010 users can download templates from the community area of Office.com by clicking New on the Microsoft Office menu. If you enable this policy setting, Office 2010 users cannot download customer-submitted templates from Office.com. However, access to templates posted by Microsoft and its partners are not affected.

This policy setting allows you configure if the document properties are encrypted. This applies to OLE documents (Office 97-2003 compatible) if the application is configured for CAPI RC4. Disabling this setting will prevent the encryption of document properties, which may expose sensitive data.

The Office 2010 Help system automatically searches Microsoft Office.com for content when a computer is connected to the Internet. Users can change this default by clearing the Search Microsoft Office.com for Help content when I'm connected to the Internet check box in the Privacy Options section of the Trust Center. If your organization has policies that govern the use of external resources such as Office.com, allowing the Help system to download content might cause users to violate these policies.