The simplicity and ease of email forging makes it one of the favorite tools for bad guys. The lack of sender authentication mechanism in Simple Mail Transfer Protocol (SMTP) allows spoofing to be used to mislead recipients about the true source of the email.

Attackers and scammers often use some form of email forgery to trick their victims. Phishing attacks, spoofed email attacks, and Business Email Compromise (BEC) attacks use one or more forms of forged emails.

This attack vector has been so exploited that, according to a report released by the FBI in May 2017, victims of BEC alone lost over $5 billion based on victim complaints worldwide since 2013.