Office 2010 Document Security Changes for Users

As a user of Microsoft Office, you should take note of a couple of important new security features in Office 2010. The concept of Trusted Documents now drives the Message Bar prompt you when you open any document that has the potential to cause damage to your computer or files. In this article, I’ll explain a couple of common scenarios where the concept of document trust in Office 2010 makes the user experience easier, while maintaining the security and integrity of your computer.

Macro and Active Control Prompts From the Message Bar

While you may be familiar with the Message Bar from Office 2007, its behavior has changed in a subtle way, for the better as far as usability goes, while still protecting you from potentially risky content.

In Office 2010, when you choose to enable macros or ActiveX controls the first time, your decision will be remembered for that document on that computer, and for your user account. Note that information about file properties is stored in the current user’s registry entry, which means if you rename the file, or move it, the Message Bar will appear again.

Office 2010 Message Bar Prompts the User When a Document With Active Content is Opened

Office 2010 Message Bar Prompts Users the First Time a Document With Active Content is Opened

As explained in the Microsoft TechNet blog at the URL below, the behavior of prompting you every time you open a document with macros or Active content in Office 2007 didn’t add any significant amount of security, since you aren’t likely to change your mind about the content from one day to the next. Furthermore, if you had accepted malicious content at one time, continuing to have the Message Bar prompt you in subsequent document editing sessions doesn’t add any protection, since your computer was likely to have been compromised the first time you enabled the content.

You can read more about the rationale for the Message Bar’s behavior on the TechNet blog at:
http://blogs.technet.com/b/office2010/archive/2009/09/28/trusted-documents.aspx

It is also possible, as discussed in my previous article on Office 2010 security features, to have your administrator create a group policy configuration that always allows certain content in Office documents, or always presents the Message Bar for other types of content. The important improvement here is that you only have to make a decision once about whether to trust content in a particular document. Your settings in the Trust Center, as well as group policies set by your administrator, can control the Message Bar behavior to allow you to work with documents containing content types you trust.

For example, the screenshot below shows the Trust Center options for Macros.

Office 2010 Trust Center – Macro Security Options Screen

To illustrate in a common scenario, suppose you create and save a document that has a macro you’ve created. In Office 2007, you were given the Message Bar asking if you wanted to enable macros every time you opened that file. In Office 2010, the Message Bar choice is remembered for that document so that you can open it as often as you like without receiving another Message Bar prompt about enabling macros – as long as you don’t rename the file or move it to another folder.

File Blocking and the Protected View

You can also change the options that control which file formats Office 2010 will open directly in edit mode or will open in the Protected View. This feature protects you from inadvertently opening files with older format types that may have vulnerabilities. Viruses and malware can be spread through documents in older file formats that exploit these vulnerabilities.

When a document is opened that is not in a trusted format or version, you will see the Protected View banner at the top of the window. If your settings allow the document type to be opened, you will have a choice of going into Edit Mode. If the File Block feature is set to disallow opening of blocked document types, the document will not open at all, and you will receive an error.

Once again, to change these settings, you can do it yourself in the Trust Center, or your administrator can create a group policy setting to allow or disallow documents created in specific file formats. As with the Message Bar settings, this can streamline your workflow, reducing the number of times you have to click to allow editing of a document.

The screenshot below shows the types of document formats that can be blocked from being opened or saved.

Office 2010 Trust Center – File Blocking Security Options Screen

Preserving Document Integrity in Office 2010 Documents

Office 2010 provides a new security feature that enables digital timestamping of documents. This can be useful for preserving the integrity of a document – and in particular, making sure you can verify the creation time of the document, and that it has not been altered in any way without your knowledge. You can find more information on the TechNet blog about the process of obtaining a digital certificate and using it to apply digital timestamps to documents at:

http://technet.microsoft.com/en-us/library/cc545900.aspx#section3a

The process of applying timestamps to Office 2010 documents in this way is not a trivial process. I doubt that many users would do this if they weren’t forced to; and many users simply may not be able to follow the process at all. The Titus Document Classification product makes it very simple for users to apply digital signatures for timestamps, as well as other security classification and document integrity purposes. Not only does this preserve the integrity of the document content – ensuring that it has not changed without your knowledge – but it also ensures that any security classification labels or markings have not been maliciously changed.

Did you find this article helpful? Are there other aspects of Microsoft Office document security that you would like to see discussed? If so, please leave a comment below or send us a note at the coordinates in the Titus Contact Us page.

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