M365EXO-028: Disallowed attachment file types set (MS.EXO.9.3)
- 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
SCuBA MS.EXO.9.3 requires that disallowed file types be determined and set, blocking at minimum click-to-run files such as .exe, .cmd, and .vbe. An attachment filter that is enabled but has an empty or insufficient block list provides no real protection. The organization must define and maintain the list of blocked extensions in line with its risk tolerance.
Valor recomendado
Attachment filter block list populated with executable/click-to-run types including at least exe, cmd, vbe, vbs, js, ps1, bat
Remediación
Populate the attachment filter block list with the file types the organization will not accept over email, ensuring click-to-run executables such as exe, cmd, vbe, vbs, js, ps1, and bat are included at minimum. Review the list against current threat trends and the organization's risk tolerance. Verify the list is non-empty and applied 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 |
| known-bad | FAIL |
| throttled | Not Assessed |
Mapeos a marcos de referencia
- NIST SP 800-53
- SI-3
- MITRE ATT&CK
- T1204.002