M365EXO-006: DKIM/DMARC/SPF validation
- Plataforma
- Entra ID / M365
- Categoría
- Advanced Threat Protection
- Severidad
- Critical
- Pilar de Zero Trust
- Applications & Workloads (peso 2)
- Fixtures de referencia
- 2
- Cobertura de ramas
- Observada: los fixtures prueban los veredictos que ejercitan
- Procedencia
- baseline
Qué comprueba
DKIM, DMARC, and SPF are email authentication protocols that verify sender identity and prevent domain spoofing. Without all three protocols properly configured, attackers can send emails that appear to originate from your organization's domain, enabling highly convincing phishing campaigns against employees, customers, and partners. Complete email authentication is a fundamental defense against business email compromise and domain impersonation.
Valor recomendado
SPF record with -all (hard fail); DKIM signing enabled for all domains; DMARC policy set to reject or quarantine with aggregate reporting enabled
Remediación
Verify that each organizational domain has a valid SPF record ending with -all (hard fail) that includes all authorized sending sources. Enable DKIM signing in Exchange Online for all custom domains and publish the DKIM CNAME records in DNS. Publish a DMARC record for each domain starting with a policy of none for monitoring, then progressively move to quarantine and finally reject once legitimate sending sources are confirmed, with aggregate reports configured for ongoing visibility.
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 |
| throttled | Not Assessed |
Mapeos a marcos de referencia
- CISA SCuBA
- MS.EXO.2.2v3, MS.EXO.3.1v1, MS.EXO.4.1v1, MS.EXO.4.2v1
- NIST SP 800-53
- SI-8
- CIS M365 Benchmark
- 2.1.9
- MITRE ATT&CK
- T1566.001