1.3.4 (L1) Ensure 'User owned apps and services' is restricted

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.

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.

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

Solution

To remediate using the UI:

- Navigate to Microsoft 365 admin center

https://admin.microsoft.com

.
- Click to expand Settings > Org settings
- In Services select User owned apps and services
- Uncheck Let users access the Office Store and Let users start trials on behalf of your organization
- Click Save

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.

See Also

https://workbench.cisecurity.org/benchmarks/17682

Item Details

Category: CONFIGURATION MANAGEMENT

References: 800-53|CM-6, 800-53|CM-7, CSCv7|5.1

Plugin: microsoft_azure

Control ID: 4be786f2cdaf6792af2863ff123284d0f40dc0fd0ebb0e442d8096150941b15a