M365TEAMS-006: Messaging policies (external communication)
- Plataforma
- Entra ID / M365
- Categoría
- Microsoft Teams Security
- Severidad
- Medium
- Pilar de Zero Trust
- Applications & Workloads (peso 1)
- Fixtures de referencia
- 3
- Cobertura de ramas
- Observada: los fixtures prueban los veredictos que ejercitan
- Procedencia
- baseline
Qué comprueba
Teams messaging policies control user capabilities within chat and channel conversations, including the ability to communicate with external users through chat. Unrestricted messaging to external users enables data exfiltration through chat, file sharing, and link sharing without the visibility and controls applied to email communication. Messaging policies must be configured to prevent sensitive data leakage through the Teams chat channel.
Valor recomendado
External chat limited to specific domains; URL preview disabled for external conversations; file sharing restricted in external chats
Remediación
Review the Teams messaging policies and restrict the ability to chat with external users to only those personnel who have a business need for cross-organization communication. Disable URL previews in conversations with external users to prevent accidental data exposure through link expansion. Consider implementing DLP policies for Teams chat to detect and block sharing of sensitive information types in external conversations.
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 |
| no-data | Not Assessed |
Mapeos a marcos de referencia
- CISA SCuBA
- MS.TEAMS.2.2v2, MS.TEAMS.2.3v2
- NIST SP 800-53
- AC-20
- CIS M365 Benchmark
- 8.2.1