1. Spam and Anti-Spam By Aditi Desai Yousuf Haider

2. Agenda Introduction Purpose of Spam Types of Spam Spam Techniques Anti spam Why Spam is so Easy Anti Spam Techniques Ongoing research Conclusion

3. Introduction Spam- unwanted “junk" e-mail sent to a large number of people to promote products or services.  1 out of 4 Network Administrators spend more than 1 hour a day combating spam  1 out of 2 organization’s bandwidth usage is at least 10% spam. Emphasis on email spam. Discussion on AntiSpam and its Techniques.

4. Purpose of Spam High potential payoffs in return for very little effort on the spammer’s part. Spammers succeed when even a small number of people reply to and purchase some spam- based offering for the spammers to succeed E.g. Lawrence Canter and Martha Siegel are two of the original, and perhaps most notorious, spammers on the Internet. These immigration attorneys earned their 15 minutes of fame by posting green card lottery ads on thousands of Usenet groups in 1993.

5. Mediums of Spam E-mail spam Instant Messaging and Chat Room spam Chat spam Newsgroup spam and forum spam Mobile phone spam Online game messaging spam Spam targeting search engines (spamdexing) Blog, wiki, and guestbook spam Spam targeting video sharing sites Noncommercial spam

6. Types of Internet Spam Unsolicited commercial mails - 68% Adult - 15% Jokes - 9% Chain letters - 4.5% Large file attachments with non-work related content - 3%.

7. Types of Spamming Techniques Email spamming  Bulk email software  Dictionary spamming  Directory harvest attack  Spambot  Pink contract

8. Security Implications of Spam Some of the security concerns of spam are:  Unwanted spam messages eat up a tremendous amount of storage space.  Large no. of messages coming in network can overload & create a DoS condition leading to serious email system downtime. Consequences: email system unavailability, improper message send receive.,  Network intrusions along with malware, Viruses,Trojan horses, Web bugs wreak havoc on networks, server, and end user systems.  Some of the spam is actually social engineering at work.

9. Cost Estimates of Spam Despite agreeing that spam is free speech, it costs people and organizations time and money Taking a real world corporate example,  25 emails/day  150/week  7800/year  2 secs. to handle each  4.33/year  $40/hr pay  173.33/user/year (???)  Each msg is 5KB  7800x 5 = 38MB clutter These figures count big for large firms with 1000+ employees.

10. Anti-Spam The Goal  Prevent or minimize the effectiveness of spammers to send spam to a large number of recipients.  Emphasis on Email Anti Spam

11. Why Spam is so Easy Cost of Harvesting or collecting email addresses. Monetary Cost of sending spam email. Computational Cost of sending spam email. Legal Cost of sending spam email. Anonymity of the sender.

12. Anti-Spam Techniques 3 Categories  End User Techniques.  Automated Techniques for Email Administrators.  Automated Techniques for Email Senders.

13. End User Techniques Address ‘Munging’  myname at email dot com  Transparent address munging more effective Disable HTML in e-mail  If not disabled might execute malicious scripts  Validate email addresses Reporting spam  Track down spammer’s ISP and report  Difficult for End user to do and will not work for botnets or netblocks.

14. End User Techniques…(contd.) Disposable Email addresses  Disposable temporary address forwards email to valid address No Response to Spam  Responding validates address Aggressive Response to Spam  Controversial, spam the spammer  Automated tools to submit forms on spammer sites  Might not work with zombies on botnets

15. Automated Techniques for Email Administrators Rule Based Systems  Parse incoming email for specific keywords or content and then apply set of rules  May have Distributed community approach Members mark spam Add to database Infer Rules from database  Valid emails may end up in Spam box

16. Automated Techniques for Email Administrators… (contd.) Challenge-Response Systems  Exploits the spammer anonymity factor.  White List – Email from addresses on white list accepted.  Black List – Email from addresses on Black List rejected  For unknown addresses : Send Challenge to unknown address If valid response received accept the original message.

17. Automated Techniques for Email Administrators… (contd.) Authentication and Reputation  Reputation system for legitimate servers.  Used in conjunction with spam filtering. Checksum-based filtering  Maintain database of checksums of spam emails  Compare chechsum of incoming email to detect DNS Based Blackhole Lists  Different kind of lists to indicate servers that send spam Greylisting  Temporarily reject messages from unknown senders  Spammers will usually not try resending

18. Automated Techniques for Email Senders Background checks on new users and customers Confirmed opt-in for mailing lists

19. Ongoing Research  Ham passwords  Attach ham passwords to email subject line to verify validity of message  Cost-based systems  Stamps - Monetary cost, micro-payments  Proof-of-work systems – Computational cost  Bonds or Sender-at-risk – Pay cost if suspicious sender

20. Conclusion Arms race between spammers and anti spam techniques Effective and efficient use of various Anti- Spam techniques as discussed can make spamming less profitable and can prove a way to help FIGHT SPAM. Distributed Community approach most effective

21. THANK YOU