M365EXO-049: Executable attachment types blocked (MS.EXO.9.5)
- Plataforma
- Entra ID / M365
- Categoría
- Advanced Threat Protection
- Severidad
- Medium
- Pilar de Zero Trust
- Applications & Workloads (peso 2)
- Fixtures de referencia
- 5
- Cobertura de ramas
- Observada: los fixtures prueban los veredictos que ejercitan
- Procedencia
- baseline
Qué comprueba
SCuBA MS.EXO.9.5 requires that click-to-run executable file types (for example .exe, .cmd, and .vbe) be blocked at the mail gateway. Microsoft Defender for Office 365 enforces this through the Common Attachment Filter on the anti-malware policy, which rejects messages carrying the listed file types outright regardless of content scanning. Executable attachments are a primary malware-delivery vector; blocking the high-risk types by extension stops the most common payloads before any detonation is required. This check inspects every anti-malware policy and confirms the Common Attachment Filter is enabled and covers at minimum .exe, .cmd, and .vbe.
Valor recomendado
Common Attachment Filter enabled on all anti-malware policies, blocking at minimum .exe, .cmd, and .vbe
Remediación
In the Microsoft Defender portal under Email & collaboration > Policies & rules > Threat policies > Anti-malware, enable the Common Attachment Filter on each policy and ensure the blocked file-type list includes the click-to-run executables (.exe, .cmd, .vbe and related types). Prefer the Standard or Strict preset security policies, which enable this by default. Confirm the policy applies to all recipients.
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 |
| filter-off | FAIL |
| gap | FAIL |
| no-policies | WARN |
| not-assessed | Not Assessed |
Mapeos a marcos de referencia
- NIST SP 800-53
- SI-3, SC-7