Microsoft Defender for Office 365
Microsoft's native email security for Microsoft 365 with XDR integration
Cloud Email SecurityPlan 1 from $2/user/month / Plan 2 from $5/user/month / included in E5
How we work:This listing is aggregated from Microsoft Defender for Office 365's official documentation, public pricing pages, community discussions (Reddit, HN, forums), and real user feedback. We do not do hands-on testing. We aggregate and organize what's already out there. Last verified February 2026.
What is Microsoft Defender for Office 365?
Microsoft Defender for Office 365 is Microsoft's native email security solution that provides protection against phishing, malware, and business email compromise for Microsoft 365 environments. It integrates deeply with the Microsoft security ecosystem including Microsoft Sentinel, Defender XDR, and Entra ID to provide cross-domain threat detection and automated investigation. For organizations heavily invested in Microsoft 365, Defender for Office 365 offers strong protection without requiring a third-party email security gateway.
Best for: Microsoft 365-centric organizations wanting native email security with XDR integration and cost efficiency through E5 licensing
Pros
- ✓ Deep native integration with Microsoft 365 and Defender XDR ecosystem
- ✓ Included in Microsoft 365 E5 — significant cost savings for E5 customers
- ✓ Automated investigation and response reduces analyst workload
- ✓ Cross-domain detection correlates email threats with identity and endpoint signals
- ✓ Continuous improvement from Microsoft's massive threat intelligence network
Cons
- ✗ Only protects Microsoft 365 — does not support Google Workspace or other platforms
- ✗ Detection efficacy for advanced threats historically behind Proofpoint and Mimecast
- ✗ Configuration complexity across multiple Microsoft security portals
- ✗ Plan 1 lacks important features like AIR and Threat Explorer
- ✗ Less effective at catching novel social engineering attacks
Key Features
→Safe Links (URL detonation and rewriting)
→Safe Attachments (sandbox analysis)
→Anti-phishing with impersonation protection
→Automated investigation and response (AIR)
→Attack simulation training
→Threat Explorer for hunting and analysis
→Real-time reports and threat analytics
→Integration with Microsoft Defender XDR
Microsoft Defender for Office 365 Comparisons
Microsoft Defender for Office 365 vs Abnormal Security→Microsoft Defender for Office 365 vs Barracuda Email Security→Microsoft Defender for Office 365 vs IRONSCALES→Microsoft Defender for Office 365 vs Tessian→Microsoft Defender for Office 365 vs Cisco Secure Email→Microsoft Defender for Office 365 vs Mimecast→Microsoft Defender for Office 365 vs Trend Micro Email Security→Microsoft Defender for Office 365 vs Proofpoint→
Quick Info
| Pricing | Plan 1 from $2/user/month / Plan 2 from $5/user/month / included in E5 |
| Model | Per-user subscription (bundled with Microsoft 365 E5) |
| Founded | 2015 |
| Cloud | Yes |
| Self-Hosted | No |
Last updated: Feb 20, 2026
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