Chapter 12. Fighting Spam

IN THIS CHAPTER

• Security and Privacy Settings

• Understanding Bayesian Filtering

• Learning About the Adaptive Filter for Junk Mail Control

• Training the Adaptive Filter

• Changing the Junk Mail Settings

• Handling Spam

• Catchall Spam

• Living Without Spam

• Organizing Mail Secrets for Power Users

Spam is an unsolicited email attempting to sell a product or service. It seems simple, but the truth is that spam is anything but simple. Spam has become a continuously waged battle between spam senders and everyone who is on the receiving end.

The first recorded commercial message was sent by an employee of DEC, based in Marlboro, Massachusetts, on May 1, 1978. It advertised a DEC computer system and was sent over ARPANET, a network run by the United States Department of Defense that was for official use only. The 1978 message provoked some complaints, but ARPANET was small and the message went unnoticed by virtually everyone else.

We can fast-forward to 1994 and the pivotal message that marked the beginning of spam as we know it today. This event was a mass mailing by a legal firm in Arizona advertising its services. Unlike the DEC example, this message generated an enormous outcry from the computing public. At that time, the Internet was still considered noncommercial, for research and other related work; however, it did not take long for spam to take hold in the following years.

The problems created by spam are enormous. A substantial amount of the Internet's resources are tied up moving spam messages from one computer to another resources that the users must pay for. Other problems created include wasted time weeding out spam from valid email and other indirect costs.

Today, we rely on two techniques to stop spam:

• Client-based screening The user's email program attempts to block spam using a number of techniques. Thunderbird's spam features are an example of this technology.

• Spam blocking services These scan a user's email, weed out spam, and forward non-spam on to the user. An example of this type of system is http://spamarrest.com/.

For those who want to learn more about spam, an excellent report can be found at http://www.ftc.gov/reports/rewardsys/expertrpt_boneh.pdf. Another good site that has a lot of related content is http://www.theregister.co.uk/2003/11/18/the_economics_of_spam/. This site has links to a number of other articles as well.

For Thunderbird users, several built-in antispam features can be used.

Thunderbird 1.5 contains a feature that attempts to block phishing messages. A phishing email is an email that requests you log on to a site with which you might have an account. However, phishing messages have URLs that do not go to the real site instead, they go to a site run by the bad guys, who then harvest your user ID and passwords. After your user ID and password are saved, these sites either redirect you to the real site or continue to attempt to get more information from you.

The end result of phishing is that you then become a victim of identity theft!

Another problem for users are emails that contain large attachments. Often these attachments are not needed, but the message body text needs to be kept. For these messages, you can choose to delete just the attachment from the message, leaving the message's body text intact so you have a copy of the message. To delete just the attachment, open the message, right-click the attachment, and select Delete (or Delete All, as appropriate).