Ghost-Sender – Universal Email Spoofing against Exchange Online
Author: Lucas Dodgson, Tobias Oberdörfer, Robin Hilber Published: June 9, 2026 Source: https://labs.infoguard.ch/posts/ghost-sender/ Summary InfoGuard Labs disclosed “Ghost-Sender,” a universal email spoofing technique against Microsoft Exchange Online. When a tenant routes inbound mail through a third-party gateway via an external MX record, an attacker can bypass that gateway entirely by speaking SMTP directly to the … Read more