Spoofing

Spoofing is an email marketing practice in which the sender will change their name, or other parts of the header, in an email message so that the message appears to come from another address. Today, SMTP does not provide authentication.  By making these changes, which can easily go unnoticed by a user who is quickly glancing at their messages, senders can impersonate others and forge emails.

Spoofing is a technique that is commonly used in spam messages and phishing attempts.  In these attempts, the spammer may use worms such as ILOVEYOU, Klez or Sober to search for email addresses in a user’s address book.  These addresses, once gathered, can then be used in the sender’s “From” field so that users may think that their contact originated the message rather than the true sender.