Ensure communication with unmanaged Teams users is disabled

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Description

This policy setting controls chats and meetings initiated through the external access channel with unmanaged Teams users (those not managed by an organization, such as Microsoft Teams (free)). This does not govern anonymous meeting join via shared link, which is controlled separately. The recommended state is: People in my org can chat and have meetings with external users who have unmanaged Microsoft accounts set to Off. Allowing users to communicate with unmanaged Teams users presents a potential security threat as little effort is required by threat actors to gain access to a trial or free Microsoft Teams account. Real-world attacks and exploits delivered via Teams over external access channels include: - DarkGate malware - Social engineering / Phishing attacks by "Midnight Blizzard" - GIFShell - Username enumeration

Méthode de vérification

Méthode d'audit: Revue manuelle

Cette recommandation ne peut pas être vérifiée automatiquement. Une analyse la liste avec ces instructions lorsque vous passez --include-manual.

Note: The focus of this control at a minimum is the Global (Org-wide default) policy. If the organization-wide setting is configured to Off, then this is also considered a passing state due to its increased restrictiveness. To audit using the UI: 1. Navigate to Microsoft Teams admin center https://admin.teams.microsoft.com/. 2. Expand External collaboration and select External access. 3. Open the Policies tab. 4. Click on the Global (Org-wide default) settings policy. 5. Verify that People in my org can chat and have meetings with external users who have unmanaged Microsoft accounts is set to Off. To audit using PowerShell: 1. Connect to Teams PowerShell using Connect-MicrosoftTeams 2. Run the following command: Get-CsExternalAccessPolicy -Identity Global Verify that EnableTeamsConsumerAccess is set to False. Organization settings: Optional passing state 1. Navigate to Microsoft Teams admin center https://admin.teams.microsoft.com/. 2. Expand External collaboration and select External access. 3. Open the Organization settings tab. 4. Verify that People in my org can chat and have meetings with external users who have unmanaged Microsoft accounts is set to Off. To audit using Pow...

Méthode de correction

Méthode de correction: Recommandation ou correctif d'infrastructure

Note: Configuring this setting at the organization level in Organization settings to Off is also a compliant remediation for this control. To remediate using the UI: 1. Navigate to Microsoft Teams admin center https://admin.teams.microsoft.com/. 2. Expand External collaboration and select External access. 3. Open the Policies tab. 4. Click on the Global (Org-wide default) settings policy. 5. Set People in my org can chat and have meetings with external users who have unmanaged Microsoft accounts to Off. 6. Click Save. To remediate using PowerShell: 1. Connect to Teams PowerShell using Connect-MicrosoftTeams 2. Run the following command: Set-CsExternalAccessPolicy -Identity Global -EnableTeamsConsumerAccess $false

Propriétés

Systèmes d'exploitation: Tous
Étiquettes: m365saas
Référence: CIS Microsoft 365 Foundations Benchmark v7.0.0 - 8.2.2 Ensure communication with unmanaged Teams users is disabled