Auto-responder features are used by Spammers to send junk emails to people.
Spammers have new tricks up their sleeves and they are not afraid to play new cards when it comes to finding new ways to send spam emails. Spammers are now utilizing web-based email accounts that are set up on free email services. They use the free services to set up multiple accounts and then turn on the out-of-office feature to perform their latest trick.
Many email services offer an auto responding feature for times when the users cannot physically reply to an email. This feature is usually used in the case that a user is out of the office and would like to let each person that sends him or her an email know this bit of information. The auto-reply is a common email courtesy extended to email senders. In the hands of a spammer it is a new way of filling the inbox of multiple email recipients.
Spammers are setting up the free email accounts utilizing the auto-reply or out-of-the-office feature to bypass spam filters and initiate their attack. Researchers have said that spammers may use an automated program to set up multiple accounts and then manipulate the auto-responder feature to send out multiple emails to recipients.
In non-techie terms: When a person receives and email thought to be an auto-reply it usually slips by spam filters because the reply comes from a legitimate sender. An auto response email may seem okay to a spam filter after examining the safe signature, DomainKey, and Sender ID.
What can you do to minimize new spam emails?
Many users can get the latest updated version of any spam filtering software either from their ISP or a 3rd party source. Because this threat is being widely discovered many spam filters are being updated to detect the new auto-responder activity. Users can always check the sources of auto-reply emails to make sure it came from an actual email message that you sent out. Many venders such as McAfee are starting to block such messages by checking the header and message content.