1. Spam By Dan Sterrett

2. Overview ► What is spam? ► Why it’s a problem ► The source of spam ► How spammers get your e-mail address ► Preventing Spam ► Possible solutions

3. What is Spam? ► Unsolicited commercial e-mail ► Sent in bulk ► Advertisements (weight loss, prescription drugs, etc)

4. Problem with spam ► Annoying ► Time consuming  You could have a hundred spam messages for each legitimate message ► Spam filters aren’t perfect ► More internet traffic ► Cheap for the spammer

5. Example Subject: Adobe Suppose we tell you that you could really lose up to 82% of your unwanted body fat and keep it off in just a few months, would you be interested? We certainly hope so! Please visit our web site - Click here!

6. Spam Stats ► In a single day in May 2003:  AOL blocked 2 billion spam messages  MSN blocked 2.4 billion spam messages

7. Where do they get my address? ► Spambots  Search engines that spider the web looking for the “@” sign. ► Newsgroups and chat rooms  Especially in big companies like AOL, people often use their screen names in chat rooms  In newsgroups people leave their actual e-mail addresses  Spammers have pieces of software that automatically extract these screen names and email addresses

8. Where do they get my e-mail address? ► Websites created specifically to attract e-mail addresses Win $1 million!!! Just type your e-mail address here!"

9. Where do they get my e-mail address? ► Websites sell your e-mail address  Created "opt-in" e-mail lists by asking, "Would you like to receive e-mail newsletters from our partners?"

10. Where do they get my e-mail address? ► "dictionary" search of the e-mail servers of large e-mail hosting companies like MSN, AOL or Hotmail  Software opens a connection with the e-mail server and sends millions of random e-mail addresses and records which ones are “live” ► Spammers sell your address to other spammers

11. Where do they get my e-mail address? ► Spammers buy e-mail addresses  Google add

12. Preventing Spam ► Spam filtering software  Simplest filters use keywords in the subject line to identify spam  Looks for words such as sex, viagra, etc.  Spammers change the spelling ► s-e-x ► Via9ra  Hard for filtering software to keep up  Sometimes blocks legitimate e-mail

13. Spam Filters ► Heuristic filters  Scan message statistically looking at word patterns and word frequency.  Spammers use shorter messages

14. Prevention ► Large ISPs tried blocking multiple e-mails with the same subject line or message body ► Unwanted side-effect  blocked e-mail newsletters  ISPs made "white lists" to identify legitimate newsletter senders.  Then spammers sidestepped the issue by inserting different random characters into each subject line and message body.

15. Prevention ► You could get an e-mail with a subject line  Women Wanted puklq  The letters “puklq” are random and are attached at the end of the subject line for each e-mail sent out. ► Organizations that list IP addresses used by spammers (Spamhaus.org is an example) ► Companies that host e-mail accounts can check the source IP address

16. Prevention ► Spammers can get around this by changing IP addresses often  The next person to receive one of these IP addresses won’t be able to send e-mail. ► Zombie machines  Viruses can be sent out to recruit “zombie machines”  Usually personal computers of unsuspecting people. Spammers route spam through these machines.  Have been used for DoS attacks on places like Spamhaus.org

17. Prevention ► Hide e-mail addresses on websites  Use javascript, etc.  Simple spambots won’t recognize it

18. Possible Solutions ► “Do Not Spam List”  Not a good idea ► Online forms  Use instead of e-mail  Drawbacks ► Need your own website ► Time consuming to send a message

19. Sources ► http://computer.howstuffworks.com/spam.h tm ► http://www.awebpage.com/stopspamemail. html http://www.awebpage.com/stopspamemail. html http://www.awebpage.com/stopspamemail. html ► http://www.htmldog.com/ptg/archives/0000 63.php