M365EXO-004: Safe Attachments policy
- Plataforma
- Entra ID / M365
- Categoría
- Advanced Threat Protection
- Severidad
- High
- Pilar de Zero Trust
- Applications & Workloads (peso 2)
- Fixtures de referencia
- 3
- Cobertura de ramas
- Observada: los fixtures prueban los veredictos que ejercitan
- Procedencia
- baseline
Qué comprueba
Safe Attachments in Microsoft Defender for Office 365 detonates email attachments in a sandbox environment to detect zero-day malware and advanced threats that signature-based scanning cannot identify. Without Safe Attachments enabled, novel malware variants delivered as email attachments may bypass traditional anti-malware filters. This defense layer is critical for organizations targeted by sophisticated adversaries using custom or polymorphic malware.
Valor recomendado
Safe Attachments enabled in Dynamic Delivery mode for all users; global settings enabled for SharePoint, OneDrive, and Teams
Remediación
Create or update the Safe Attachments policy to use Dynamic Delivery mode, which delivers the email body immediately while attachments are scanned, minimizing user impact while maintaining protection. Enable Safe Attachments for SharePoint, OneDrive, and Teams in the global settings to extend file detonation protection beyond email. Assign the policy to all users and monitor the Threat Explorer for detections to validate policy effectiveness.
Veredictos probados con fixtures
Cada veredicto de esta tabla está probado por un fixture de referencia en la suite de pruebas que valida el módulo. La tabla se deriva de la última ejecución en verde; no puede editarse a mano.
| Escenario | Veredicto esperado |
|---|---|
| clean | PASS |
| known-bad | WARN |
| throttled | Not Assessed |
Mapeos a marcos de referencia
- CISA SCuBA
- MS.DEFENDER.3.1v1
- NIST SP 800-53
- SI-3
- CIS M365 Benchmark
- 2.1.4