Security Practitioner’s Guide to Email Spoofing and Risk Reduction

This report explains how email spoofing works—covering SMTP envelope vs. headers, methods attackers use to send spoofed mail (open relays, compromised servers, brute-forced accounts), and common abuse such as sextortion and business email compromise—and recommends mitigation controls and operational steps including SPF, DKIM, and DMARC configuration and monitoring.