M365EXO-009: Mailbox auditing enabled
- 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
Mailbox auditing records actions performed on mailbox contents by the mailbox owner, delegates, and administrators, providing critical forensic evidence during security investigations. Although mailbox auditing is enabled by default in Microsoft 365, organizations may have disabled it for specific mailboxes or may not have verified that the default audit actions are sufficient. Without mailbox auditing, unauthorized mailbox access and data exfiltration cannot be detected or investigated.
Valor recomendado
Mailbox auditing enabled for all mailboxes; default audit actions include MailItemsAccessed, Send, and SoftDelete for all logon types
Remediación
Verify that mailbox auditing is enabled organization-wide by checking that the AuditDisabled parameter is set to False on all mailboxes. Review the audited actions for each logon type (Owner, Delegate, Admin) and ensure that critical actions such as MailItemsAccessed, Send, SoftDelete, HardDelete, and UpdateFolderPermissions are being recorded. For mailboxes that have audit disabled, re-enable auditing and investigate why it was disabled to rule out malicious tampering.
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
- CISA SCuBA
- MS.EXO.13.1v1
- NIST SP 800-53
- AU-2, AU-3
- CIS M365 Benchmark
- 3.1.1