1.4.7.2.2.4 Ensure 'Document Behavior if File Validation Fails' is set to Enabled (Open in Protected View/Unchecked for 'Do not allow edit')

Information

his policy setting controls how Office handles documents when they fail file validation. The recommended state for this setting is: Enabled. (Open in Protected View and Unchecked for 'Do not allow edit) Disabling or not configuring this setting allows users to open and edit files that have failed file validation outside of Protected View. As a result, malicious code or users could become active on user computers or the network. For example, a malicious user may purposely put invalid data in a file. The invalid data could force the program to fail or execute its code in an unexpected manner, giving the malicious user control of the application.

Solution

To implement the recommended configuration state, set the following Group Policy setting to Enabled. User Configuration\Administrative Templates\Microsoft Excel 2016\Excel Options\Security\Trust Center\Protected View\Set Document Behavior if File Validation Fails Impact: By default, users can only open files in Protected View after the files fail validation to help prevent malicious code from running on user computers or the network. In this way, the application is protected from attacks attempting to induce unexpected execution paths. You can block files from opening at all, but this also prevents users from accessing any data in the file. Using this setting allows the application to open files, and thus users to view valid data and detect invalid data that is visible. However, users cannot correct invalid data in the file. To do so, users must open such files on another isolated computer where this setting is set to a lower security level.

See Also

https://workbench.cisecurity.org/files/569

Item Details

Category: CONFIGURATION MANAGEMENT

References: 800-53|CM-6b.

Plugin: Windows

Control ID: fd14bc68af9cd88c86498c85d50edc1d97175b0957f9a814446b2c675350d600