check before: 2025-07-01
Product:
Exchange, Microsoft 365 suite, Purview Communication Compliance, Purview Data Loss Prevention
Platform:
Online, US Instances, Web, World tenant
Status:
In development
Change type:
New feature, User impact, Admin impact
Links:
Details:
Summary:
Microsoft Purview Data Loss Prevention for Exchange Online will enhance detection by evaluating the actual content of files, not just their extensions. This update, rolling out from mid-July to mid-October 2025, ensures more robust compliance and security. Admins can configure rules based on true file types without prior action.
Details:
Coming soon for Microsoft Purview | Data Loss Prevention for Microsoft Exchange Online:
Before this rollout, Exchange Online relies only on the file extension (such as .docx and .pdf) to identify the type of an attachment but this approach can be bypassed if a file is renamed with a misleading extension. To address this, we're enhancing our detection logic to go beyond just the visible file extension. After this rollout, even if a file's extension is altered, Exchange will evaluate the actual content of the file to determine its true type. This ensures that policies based on file type (such as File extension is…) will remain effective and secure, even when attachments are renamed or disguised. This improvement provides you with a more robust and reliable way to enforce compliance and security rules around file sharing.
This message is associated with Microsoft 365 Roadmap ID 493291.
[When this will happen:]
Public Preview: We will begin rolling out mid-July 2025 and expect to complete by late August 2025.
General Availability (Worldwide): We will begin rolling out late August 2025 and expect to complete by late September 2025.
General Availability (GCC, GCC High): We will begin rolling out late August 2025 and expect to complete by mid-October 2025.
Change Category:
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Scope:
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Release Phase:
General Availability, Preview
Created:
2025-05-31
updated:
2025-05-31
Public Preview Start Date
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Task Type
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Docu to Check
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MS How does it affect me
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MS Preperations
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MS Urgency
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MS workload name
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linked item details
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Pictures
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summary for non-techies**
Microsoft is updating its Data Loss Prevention (DLP) system in Exchange Online to analyze the actual content of files rather than just their extensions, enhancing security by accurately identifying file types and preventing disguised harmful files from bypassing security measures.
Direct effects for Operations**
Increased Detection of Non-Compliant Files
With the new detection logic, there will be an increase in the number of detections for non-compliant files that were previously undetected due to misleading file extensions. This could lead to a higher volume of alerts and incidents for users who may not be aware of the changes in detection criteria.
- roles: Compliance Officer, IT Support Specialist
- references: https://learn.microsoft.com/powershell/module/exchange/new-dlpcompliancerule?view=exchange-ps, https://www.microsoft.com/microsoft-365/roadmap?filters=&searchterms=493291
User Confusion and Increased Compliance Training Needs
Users may experience confusion regarding file sharing policies as the detection of true file types may lead to unexpected alerts or blocks on legitimate files. This necessitates additional training and communication to ensure users understand the new compliance measures and how to avoid issues.
- roles: End User, Compliance Officer
- references: https://learn.microsoft.com/powershell/module/exchange/new-dlpcompliancerule?view=exchange-ps, https://www.microsoft.com/microsoft-365/roadmap?filters=&searchterms=493291
Configutation Options**
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Data Protection**
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IT Security**
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explanation for non-techies**
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** AI generated content. This information must be reviewed before use.
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Last updated 2 weeks ago
