2.9 - Ensure users installing Word, Excel, and PowerPoint add-ins is not allowed

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This audit has been deprecated and will be removed in a future update.

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Information

By default, users can install add-ins in their Microsoft Word, Excel, and PowerPoint applications, allowing data access within the application.

Do not allow users to install add-ins in Word, Excel, or PowerPoint.

Rationale:

Attackers commonly use vulnerable and custom-built add-ins to access data in user applications.

While allowing users to install add-ins by themselves does allow them to easily acquire useful add-ins that integrate with Microsoft applications, it can represent a risk if not used and monitored carefully.

Disable future user's ability to install add-ins in Microsoft Word, Excel, or PowerPoint helps reduce your threat-surface and mitigate this risk.

Impact:

Implementation of this change will impact both end users and administrators. End users will not be able to install add-ins that they may want to install.

NOTE: Nessus has not performed this check. Please review the benchmark to ensure target compliance.

Solution

To prohibit users installing Word, Excel, and PowerPoint add-ins, use the Microsoft 365 Admin Center:

Select Settings from the navigation pane.

Select Org Settings from the navigation pane.

Under Services select User owned apps and services.

De-Select Let users access the Office Store and Let users start trials on behalf of your organization.

Click Save.

Default Value:

Let users access the Office Store is Checked

Let users start trials on behalf of your organization is Checked

See Also

https://workbench.cisecurity.org/files/3729