Part of Microsoft Defender for Office 365: before delivering a message, it detonates attached files in a sandbox to catch previously unseen malware, and it also scans files stored in SharePoint, OneDrive and Teams.
Read more: Microsoft Learn
In the Ultra Transcenders books
Each book explains Safe Attachments in context, with comparison tables and the common traps.
Terms in this definition
- Microsoft Defender for Office 365
Microsoft's protection service for email and collaboration tools. Its basic plan covers impersonation, Safe Attachments, Real-time detections and Safe Links; the higher plan layers on Attack simulation training, automated investigation and response, and Threat Explorer.
Related terms
- Defender for Office 365 Plan 1
The entry tier of Defender for Office 365. Safe Links, Safe Attachments and impersonation protection guard mail and collaboration tools against phishing, business email compromise and zero-day malware. Bundled with Microsoft 365 Business Premium, and from 1 July 2026 with Office 365 E3 and Microsoft 365 E3 too.
- Dynamic Delivery
A Safe Attachments option where the body of a message reaches the recipient straight away, with placeholder files standing in until the attachments have been scanned. It is only available for mailboxes in Exchange Online.