7 Lessons Learned from Replacing 200+ Secure Email Gateways

Secure email gateways were built for yesterday’s threats. Today’s attackers use social engineering, account takeover, and multi-stage phishing that easily slips past rule-based defenses. As organizations move to Microsoft 365 and Google Workspace, many are rethinking their SEG—and replacing it altogether.

In this white paper, Abnormal AI shares seven key lessons from helping organizations retire more than 200 SEGs and move to modern, AI-powered email security. You’ll see real attack examples, migration best practices, and results from companies that have already made the switch.

What you’ll learn

  • Why “the great SEG migration” is underway—and how native cloud email security plus AI now covers what SEGs used to do.

  • How SEG rules and signatures fail against image-based lures, multi-step phishing, and business email compromise (BEC).
  • How account takeovers are rising, with compromised internal accounts launching convincing lateral phishing campaigns.
  • The evolution from network-based SEGs to API-based cloud email security—and what that means for your architecture.
This content is brought to you by Abnormal AI, the human behavior security platform that uses machine learning to stop advanced email and collaboration attacks—protecting more than 3,200 organizations, including 20% of the Fortune 500.
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