526780 – Microsoft Teams: Tenant-Owned Domain Impersonation Protection for Teams Messaging

Product:

Teams

Platform:

Android, iOS, Mac, Web, Windows Desktop, World tenant

Status:

Launched

Change type:

Links:

MC1187679

Details:

Identify if an external user comes from a domain that is impersonating the recipient tenant's own domains, during their initial contact with an enterprise user via Teams messages.

Change Category:
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Scope:
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Release Phase:
General Availability

Created:
2025-11-17

updated:
2025-12-18

Docu to Check

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MS workload name

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summary for non-techies**

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Direct effects for Operations**

Please, look at the most relevant linked item for details

explanation for non-techies**

Imagine you're at a large networking event. You meet someone who introduces themselves as a representative from a well-known company. They have a business card that looks almost identical to the official ones from that company, but there's a tiny detail that's off. If you're not careful, you might not notice this and could end up sharing sensitive information with someone who isn't who they claim to be.

In the digital world, something similar can happen with email and messaging domains. When you receive a message from someone claiming to be from a particular company, it's important to ensure that the domain (the part of the email address after the '@' symbol) is legitimate and not an impersonation. Microsoft Teams is introducing a feature to help with this. It's like having a security guard at the networking event who checks the authenticity of each business card before you engage in conversation.

This new feature in Microsoft Teams will identify if an external user is trying to contact someone within your organization using a domain that looks like one of your own but isn't. This is particularly important during the initial contact when you're less familiar with the person or their organization. It's like having a tool that automatically checks and verifies the authenticity of that business card before you even start talking to the person.

By implementing this feature, Microsoft Teams helps protect organizations from potential impersonation attacks, ensuring that communications are genuine and secure. It's a way to ensure that when you're engaging with someone new, you're actually talking to who you think you are, keeping your conversations and data safe.