Nuisance or erroneous bounced email messages
Spammers commonly forge the headers of messages they send, making it appear as though they originated elsewhere. This is called "spoofing". Spammers harvest vast numbers of email addresses, or even guess common email addresses, and then put these addresses in the "To:" and the "From:" fields of the millions of email messages they send out. Some of the messages they send will end up bouncing, and when they do, the forged address in the "From:" (or "Sender") field, which may be yours, receives a non-delivery receipt (or bounce).
There are also viruses, such as Klez and Sobig, which spoof the sender's address. An infected computer sends out infected messages and puts addresses in the "To:" and "From:" fields that it finds somewhere on the infected computer (the email addresses it finds don't have to be in the contacts lists of the email program, but could even be, for example, in a stored document or cached web page). Again, if the "To:" address doesn't work, the message bounces, but it bounces back to the "From:" address, which may be yours.
To make sure that your computer is not infected, UITS recommends that you update your virus pattern file and scan your computer. For help, see For Symantec virus protection software, what are my options for updating the virus definitions? and Using Symantec/Norton AntiVirus Corporate Edition in Windows, how do I immediately scan a file, folder, or drive for viruses? If you find no viruses, then you can assume that your email address was spoofed.
There is unfortunately very little you can do about these messages, because the only way to trace the spammer or the infected computer is by investigating the full headers of the original message sent (not the bounced message), and only the receiver of the original message can enable those headers. The receiver in many of these "bounced email" cases is the automatic mailer from the domain of the non-working address that was in the "To:" field. Normally, these automatic "bounced email" messages do not contain the full headers of the original message sent. You could try to contact the organization whose automatic mailer sent you the bounce message and ask for the full headers, but this takes a lot of effort and isn't usually successful.
For tips on how to reduce the opportunities for both spammers and viruses to get your email address, see:
