A new attack technique named SMTP Smuggling can allow malicious actors to send out spoofed emails that bypass authentication mechanisms. The attack technique targets the Simple Mail Transfer Protocol. An attacker can abuse differences in the way outbound and inbound SMTP servers interpret a sequence indicating the end of message data.

Read more: https://www.securityweek.com/smtp-smuggling-allows-spoofed-emails-to-bypass-authentication-protocols/