Ensure 'User owned apps and services' is restricted

MediumLevel 1Manual reviewm365

Description

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

How it is checked

Audit method: Manual review

This recommendation cannot be checked automatically. A scan lists it with these instructions when you pass --include-manual.

To audit using the UI: 1. Navigate to Microsoft 365 admin center https://admin.microsoft.com. 2. Expand Settings > Org settings. 3. In Services select User owned apps and services. 4. Verify that Let users access the Office Store and Let users start trials on behalf of your organization are not checked. To Audit using PowerShell: 1. Connect to the Microsoft Graph service using Connect-MgGraph -Scopes "OrgSettings-AppsAndServices.Read.All". 2. Run the following Microsoft Graph PowerShell command: $Uri = "https://graph.microsoft.com/beta/admin/appsAndServices/settings" Invoke-MgGraphRequest -Uri $Uri 3. Verify both isOfficeStoreEnabled and isAppAndServicesTrialEnabled are False.

How it is fixed

Fix method: Guidance or infrastructure patch

To remediate using the UI: 1. Navigate to Microsoft 365 admin center https://admin.microsoft.com. 2. Expand Settings > Org settings. 3. In Services select User owned apps and services. 4. Uncheck Let users access the Office Store and Let users start trials on behalf of your organization. 5. Click Save. To remediate using PowerShell 1. Connect to the Microsoft Graph service using Connect-MgGraph -Scopes "OrgSettings-AppsAndServices.ReadWrite.All". 2. Run the following Microsoft Graph PowerShell commands: $uri = "https://graph.microsoft.com/beta/admin/appsAndServices" $body = @{ "Settings" = @{ "isAppAndServicesTrialEnabled" = $false "isOfficeStoreEnabled" = $false } } | ConvertTo-Json Invoke-MgGraphRequest -Method PATCH -Uri $uri -Body $body

Properties

Operating systems: Any
Tags: m365saas
Reference: CIS Microsoft 365 Foundations Benchmark v7.0.0 - 1.3.4 Ensure 'User owned apps and services' is restricted