1. Gold Country Computer Learning Center March 2007 Spam Email Roger Thornburn

2. Gold Country Computer Learning Center Email spam Roger Thornburn March 2007 2 What is Spam Needs to meet 2 requirements Unsolicited Bulk Name comes from a Monty Python skit Monty Python's spam video Monty Python's spam Mostly commercial 25% - Products20%- Financial 19% - Adult9%- Scams 7%- Health7%- Internet Not Spam: Jokes from friends Newsletters you signed up for

3. Gold Country Computer Learning Center Email spam Roger Thornburn March 2007 3 A Few Statistics Amount of Spam 90 Billion spam emails a DAY (Feb 2007) Average of 50 spam emails a day – per email address 94% of all email is spam Sources of Spam US – 23% China – 20% Russia -10% South Korea – 6% Surprise! 28% reply to spam email 8% purchase from spam email

4. Gold Country Computer Learning Center Email spam Roger Thornburn March 2007 4 Current Situation IP addresses last 4 hours June 2006 – 35M new domains, 32M not paid Hi jacked mail servers – listed as spammers Creates problem for legitimate users Use of “Zombie” PC’s and the Botnet Maybe 1 in 4 PC’s infected. Image spam Hard for a computer to read Hi growth from 0 to 25% of spam Getting your email address Dictionary attackSpam bots (websites) Infected computersVendors/subscriptions

5. Gold Country Computer Learning Center Email spam Roger Thornburn March 2007 5 Spam Safety tips Encrypt your email address (not in a dictionary) Use a fake email address where possible Use bcc to send an email to many people Don’t open spam and set Outlook Express to “Block images…..” Avoids confirming your email Don’t reply to spam – again it confirms you’re real! Don’t post your email address on a website. Uncheck all those “subscribe” boxes Unsubscribe from reputable companies only Use a spam filter

6. Gold Country Computer Learning Center Email spam Roger Thornburn March 2007 6 Spam Filtering Techniques Rules based Matches specific words in the To, From, Subject or Body of the email Very specific – can only make an exact match Bayes filter/Fuzzy logic Uses a mathematical set of probabilities, gathered from being told what’s “spam” and what’s “ham” Needs to “learn” and kept up to date Black list Blocks specific “From” addresses. Not very effective today – new domain every 4 hours! Good for blocking family/friends or newsletters

7. Gold Country Computer Learning Center Email spam Roger Thornburn March 2007 7 Spam Filtering Techniques (cont.) On-line Database (DNSBL) Can work well - if accurate. Can easily stop legitimate emails as well. Signature analysis for specific emails White list List of email addresses you will accept email from Challenge/response systems Needs to be kept up-to-date Most effective method Important!: No spam filter is perfect. The worst thing is putting legitimate emails in your Spam/Junk/Bulk mail folder. It’s essential to check this folder so you can receive your good email, as well as train the filter.

8. Gold Country Computer Learning Center Email spam Roger Thornburn March 2007 8 Reducing Spam in Real Life! Different if using Web mail or POP mail Web mail is when you use your internet browser (Internet Explorer or Firefox, etc) to read and send your email. POP mail is when you use an email client (a program such as Outlook/Express, Thunderbird, Endura, etc.) to read and send your email. With POP mail, the email messages are downloaded to your computer – can be read and new ones composed, without beeing connected to the internet. To read or compose messages in Web mail, you must be connected to the internet Many email accounts can be accessed by either/both

9. Gold Country Computer Learning Center Email spam Roger Thornburn March 2007 9 Web Mail All your email stays on the Web mail server You have little control Large providers such as Yahoo, Google, Hotmail, etc. provide excellent spam filtering – using a combination of all the above techniques Any legitimate emails in the spam/junk box, must be identified – now added to your white list Yahoo has AddressGuard Create a separate email address for each person or class of persons Many of the smaller ISP’s/email providers, aren’t as sophisticated.

10. Gold Country Computer Learning Center Email spam Roger Thornburn March 2007 10 POP 3 Spam filter sits between the mail server and your email client Many ISP’s or email servers have own spam filter Yahoo (SBC, AT&T, Pacbell, etc.) use same as Web mail Can be harder to check spam folder – may need to configure Huge selection of programs – freeware to $$’s http://spamlinks.net/filter-client-win.htm http://spamlinks.net/filter-client-win.htm Use different techniques – either singly or in combination. Some are tightly integrated to the email client

11. Gold Country Computer Learning Center Email spam Roger Thornburn March 2007 11 POP3/Outlook Express Examples Outlook Express –Rules Text matching – limited Good for White list – can import address book K-9 Freeware Uses Bayesian technology – so must train Plus has White list and Black list Regex filters for advanced users Easy interface – but not elegant Computer Associates ($30) White list Integrated to Outlook/Express – easy to use

12. Gold Country Computer Learning Center Email spam Roger Thornburn March 2007 12 More Examples MailWasherPro ($30) Freeware version available Combination of Bayes, White list, Black list, DNSBL, User filters and Signature Reviews email on the server Spam is removed before download Save time with dial up Easy to use

13. Gold Country Computer Learning Center Email spam Roger Thornburn March 2007 13Phishing Scams to trick users to reveal personal information Normally an official looking email Directed to a fraudulent website 2004 2006 Losses from phishing attacks: $137 million$2.8 billion # US adults who received at least one phishing e-mail:57 million 109 million Number of victims:53 thousand2.25 million Per-victim loss:$257 $1,244 Money recovered by consumers: 80% 54% Don’t click a link in an email Call your bank or credit card company if suspicious Check the website is secure (https://xxxxx)

14. Gold Country Computer Learning Center Email spam Roger Thornburn March 2007 14 Useful Links http://en.wikipedia.org/wiki/Spam_e-mail http://en.wikipedia.org/wiki/Spam_e-mail Wikipedia Reference http://spam.abuse.net/userhelp/ http://spam.abuse.net/userhelp/ Links to resources and anti-spam filters http://spamlinks.net/ http://spamlinks.net/ More links to many anti spam resources http://spamlinks.net/filter-client-win.htm http://spamlinks.net/filter-client-win.htm (More spam filters) http://spam-filter-review.toptenreviews.com/ http://spam-filter-review.toptenreviews.com/ Review of some spam filters http://keir.net/k9.html http://keir.net/k9.html Freeware Bayes filter (plus White and Black list) http://shop.ca.com/STContent/landingpages/Antispam/ASPM001/index.aspx?sc_lang=en-US http://shop.ca.com/STContent/landingpages/Antispam/ASPM001/index.aspx?sc_lang=en-US Computer Associates anti spam program (Or Google ca spam). Paid, easy to use White list – integrates to Outlook Express. http://www.mailwasher.net/ http://www.mailwasher.net/ Mail Washer free and paid anti-spam versions. Uses multiple methods for detection http://www.spambutcher.com/ http://www.spambutcher.com/ Spam Butcher – fuzzy logic anti-spam

15. Gold Country Computer Learning Center Email spam Roger Thornburn March 2007 15Summary Web mail Dependant on the ISP/Web mail provider Larger providers often provide configurable options Yahoo AddressGuard is a good solution MUST go into JUNK/BULK/SPAM folder to mark good emails – regularly POP3 mail Most effective method is White list (or safe senders list) – but needed to be kept up-to-date. Using built in Rules of Outlook Express works fine Purchased product – often more convenient. Above all – Protect Your Email Address!!