BEC causes more financial loss than any other cybercrime category, and it frequently passes authentication because the mailbox is real.
The metrics that matter#
- Authentication pass rate: share of mail passing SPF, DKIM, and DMARC alignment. Healthy: 99% or higher.
- Spam complaint rate: Gmail enforces at 0.3%; stay under 0.1%.
- Hard bounce rate: under 2%; above 5% triggers platform reviews.
- Inbox placement: above 90% across major providers via seed tests.
- Engagement: click and reply rates by segment; opens are unreliable after Mail Privacy Protection.
Where to read them#
- Google Postmaster Tools for Gmail domain reputation, spam rate, and authentication.
- Microsoft SNDS and JMRP for Outlook.com IP reputation and complaints.
- Your ESP's delivery and bounce reports.
- DMARC aggregate reports for authentication by source.
Improving the numbers#
- Require MFA on all mailboxes and disable legacy authentication protocols.
- Alert on new inbox rules that forward or delete mail, a common attacker persistence step.
- Verify payment changes by phone using a known number, never the one in the email.
- Flag external mail with display names matching internal staff.
Frequently asked questions#
How is BEC different from phishing?
Phishing casts wide for credentials; BEC is targeted social engineering for money, often using a real hijacked account.