Spoofing is English for “deception, swindle” and means making a fake message look real. Spoofing is used in fraudulent emails to swindle trust. Often a sender known to the recipient is faked. This is easily possible because the SMTP protocol on which email transmission is based does not require authentication. Ultimately, the email recipient should be persuaded to take an action, such as clicking on a malware-infected link or attachment.

Similar scams are phishing and CEO fraud.