Word must be configured to warn when opening a document with custom XML markup.

From Microsoft Word 2013 STIG

Part of DTOO426 - Custom XML markup warning

SV-53598r1_rule Word must be configured to warn when opening a document with custom XML markup.

Vulnerability discussion

This policy setting specifies how Word behaves when opening a document that contains custom XML markup. Versions of Word that are distributed by Microsoft after January 10, 2010 no longer read the custom XML markup that may be contained within (.docx, .docm, .dotx, .dotm or .xml files. The new versions of Word 2007, Word 2010, and Word 2013 can still open these files, but any custom XML markup is removed. Configuring this setting will prompt the user with a warning, notifying of the lost of the XML markup. While this is the default setting, explicitly configuring the setting will ensure users are prompted.

Check content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Word 2013 -> Word Options -> Advanced -> "Custom markup warning" is set to "Enabled: Prompt". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\word\options Criteria: If the value custommarkupwarning is REG_DWORD = 1, this is not a finding.

Fix text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Word 2013 -> Word Options -> Advanced -> "Custom markup warning" to "Enabled: Prompt".

Pro Tips

Lavender hyperlinks in small type off to the right (of CSS class id, if you view the page source) point to globally unique URIs for each document and item. Copy the link location and paste anywhere you need to talk unambiguously about these things.

You can obtain data about documents and items in other formats. Simply provide an HTTP header Accept: text/turtle or Accept: application/rdf+xml.