Explained: SMTP smuggling

SMTP smuggling is a technique that allows an attacker to send an email from pretty much any address they like. The intended goal is email spoofing—sending emails with false sender addresses. Email spoofing allows criminals to make malicious emails more believable.

Let’s take a closer look at what it is exactly, and how cybercriminals can use it.

The first thing we need to look at is the Simple Mail Transfer Protocol (SMTP), a protocol that allows the exchange of …

address addresses attacker closer criminals cybercriminals email emails email spoofing explained malicious malicious emails send smtp smtp smuggling smuggling spoofing