Every time a new virus starts spreading across the Internet, we spend a good amount of time explaining to clients why they are receiving notifcations (bounce messages) that an "email containing a virus" was sent from them. Thought it might be good general info to post here also. Viruses spread by infecting a user PC, then replicating themselves via e-mail and sending out a copy to the e-mail addresses found on the infected PC. It is very important, therefore, to maintain some type of virus protection on your local PC's (such as MacAfee or Symantec) and keep it up-to-date. Viruses often "cloak" themselves by sending out messages FROM somebody other than the infected PC. So, if you are receiving notifications that a virus was sent from your e-mail address (or domain name), then one of two things has occurred: 1. Your PC is infected with the virus and is sending out these messages 2. Some other PC is infected with the virus and is sending out the messages, and using YOUR address as the FROM address. This means that when another e-mail system catches the virus, YOU get the notification (even though it is likely you had nothing to do with it.) Again, viruses are often programmed to cloak their origin and therefore send out messages from a randomly selected domain found on the infected PC. That means that ANYONE YOU HAVE EVER corresponded with via e-mail could pick up the virus and, because your e-mail address is on their PC, the virus can send out copies of itself making it appear to come FROM you.
Most of the new mass mailer viruses attacking Outlook are using a from line forgery most likely found in the infected users address book. Webbie could do a tutorial on viewing expanded header information, so if you ever do have to contact the abuse department of your ISP, this is the first thing they are going to ask for.
