Quick fix
Inventory every legitimate sending platform and verify SPF and DKIM alignment.
What this finding means
SecuTest queries `_dmarc.example.com` for a single record beginning with `v=DMARC1`. DMARC builds on SPF and DKIM alignment to tell receivers how to handle unauthenticated mail. Absence does not prove that spoofed messages will be accepted, but it removes the domain owner's explicit enforcement signal.
Associated attack or threat scenario
How the attack or failure scenario works
Direct-domain spoofing is the use of the organization's visible From domain in a forged message. DMARC checks whether SPF or DKIM passes and aligns with that visible domain. Without a DMARC record, receivers cannot apply the domain owner's requested quarantine or rejection policy.
Conditions and limitations
- An attacker can submit mail with the protected domain in the visible From header.
- The message lacks an aligned SPF or DKIM pass.
- The receiver accepts or merely flags unauthenticated mail because no domain policy requests enforcement.
Why it matters
Step-by-step fix
Where to make the change
- The authoritative DNS zone for the registrable domain.
- The outbound or inbound mail platform when sender authorization, signing, or routing is involved.
- The DMARC reporting mailbox or reporting service when aggregate reports are required.
Remediation procedure
- Inventory every legitimate sending platform and verify SPF and DKIM alignment.
- Create a dedicated aggregate-report mailbox or reporting service.
- Publish one DMARC TXT record at `_dmarc.example.com`, initially using `p=none` only while collecting data.
- Analyze reports, remediate unauthenticated senders, then progress to `p=quarantine` and `p=reject`.
Commands and configuration examples
Replace example values with the hostname, selector, IP address, port, provider, or policy values shown in your SecuTest evidence. Review every example before production use.
_dmarc.example.com. 3600 IN TXT "v=DMARC1; p=none; rua=mailto:dmarc-reports@example.com"
_dmarc.example.com. 3600 IN TXT "v=DMARC1; p=reject; pct=100; rua=mailto:dmarc-reports@example.com"
dig +short TXT _dmarc.example.com
Verify the fix
- Run `dig +short TXT _dmarc.example.com` and confirm one `v=DMARC1` record.
- Send messages through every production sender and inspect `Authentication-Results` for aligned SPF or DKIM.
- Review aggregate reports for unknown and legitimate sources.
- Test enforcement with a controlled unauthorized sender before moving to `p=reject`.
After DNS, CDN, certificate, mail, or application propagation completes, run a fresh SecuTest scan and compare the new evidence with the original finding.
Common mistakes
- Publishing DMARC before all legitimate senders have aligned SPF or DKIM.
- Placing the record at the root domain instead of `_dmarc`.
- Assuming SPF pass alone is enough when the envelope-from domain is not aligned with the visible From domain.