Group 2: Sam Yeol Dan, Dylan Samuel Kuhnen, A ram Lee, Karmen Li

Email Spam Filters
As long as there has been email there has been spam, both legitimate and illegitimate companies use email as a method of extremely cheap advertising for their products. To compensate with the increase in spam, developers have produced spam mail filters. These filters attempt to use different techniques to block spam. The main problem with filters being false-positives and false-negatives.

Spam
Indiscriminately sent emails to new recipients.

Spam filter
Program which automatically analyzes email to determine whether or not it is spam.

False Positive
When a spam filter recognizes a friendly email as spam.

False Negative
When a spam filters fails to acknowledge a spam email, as spam.

Filtering Process
Spam mail filters work differently depending on what type of filter they are. However all filters follow a basic principle to determine whether or not an email is spam. First the filter checks incoming email for phrases within the email which violate its programming rules. Next the filter assigns points for each time one of these rules is broken, a set amount of points depending on the severity of the rule broken. Finally once the email has been thoroughly checked, the filter compares the emails score, to a threshold set by the user. If the email score exceeds the threshold it is sent directly to the Junk Mail folder, or immediately deleted.



User Defined Filters
Automatically removes spam based on rules set by the user. User can set the certain rules for acceptable sources and subject matter.

Header Filters
Examine the header of incoming email, both to check if it is from a known spammer, or if it is forged, which indicates spam.

Language Filters
Blocks any email which is not in the language of your choice.

Content Filters
Based on a very general set of rules that analyze the text of an email to determine if it is spam.

White Lists and Black Lists
Allow the user to block all emails from a specific user or website.

Permission Filters
A form of challenge response system, blocking all e-mails that doesn’t come from a source that you have authorized for access to your system

Password Filters
Blocks e-mail without password in the subject in line.

Rules Based Filters
Blocks e-mail depending on a pre-determined set of rules, help to catch 90-95% of spam by finding exclamation points, specific words and phrases, malformed header, and odd punctuations

Community Filters
Blocks e-mail based on community agreement that is junk.

Adaptive/Bayesian Filters
Utilize a mathematical formula to examine the content of a message.

Top Selling Products
Symantec Brightmail

Microsoft ISA 2004/2006

Mcafee - Spamkiller



Norton Internet Security 2007

Kaspersky Anti-Spam

NOD32

Barracuda Spam Firewall

ZoneAlarm

Mailsweeper

Fortimail

James Mccalla
James McCalla was charged 11.2 Billion dollars for sending 280 million spam messages. He forged the header and return address so the emails appeared to come from a legitimate company. Under the state law, the CIS corporation who was cited as the sender in these spam emails, was entitled to $10 for every illegal email. James was also banned from the internet for three years following this indiscretion. CIS admits it will likely never see any of the money it was awarded as punitive damages, however they are pleased with the message that this ruling sends to Spammers.

Spam Scams
These are possibly the most important reason for spam filters, to protect users from becoming victims of scams in emails they receive.

The "Nigerian" Email Scam
In this email scam, the sender will pretend to be an official of the former Nigerian government, or another African country, they claim that their money is somehow tied up for a limited time. They offer to transfer large sums of money into your account, in exchange for money now to help them access their money. They then ask you to transfer money to cover transfer costs, transaction fees, and attorney fees. Some scammers even suggest that the person visits the country in question to verify the legitimacy of their claims. However soon the "official" vanishes with the money they have been sent. However in certain cases more extreme measures are used, and those who fall prey to this scam are threatened and harassed when they refuse to send further funds.

Phishing
Phishing is a scam when a sender will send an email pretending to be a company you deal with. They will then ask you to update, validate, or confirm your information. They then use this personal information to steal your identity.

Check Overpayment Scams
These scams involve a person who will give you a cheque, however they will provide a reason for the cheque being a greater sum than initially agreed upon, and they will ask you to write them another cheque, or transfer money to their account. The cheque then turns out to be fake, and from here two different scenarios can take place. First, you may be out for the amount of money that you have sent them. Second, now that they have your account information, they may use that to further remove funds from your account, or steal your identity.

New Technology
Everyday new technology is being developed by spammers to find ways around the filtering systems. Some methods include:

Content-transfer-encoding: the message is sent completely encoded so that filtering systems won’t trash it because it doesn’t detect any key words, such as “buy it now!”, or "limited time only!". -An example would be:

Reply-To:  Message-ID: <031c06e62c2b$8445d5b2$5da01aa2@qjwmpp> From:  To: Lower bills Subject: ** Approved. Date: Tue, 24 Sep 2002 11:24:41 +0600 MiME-Version: 1.0 Content-Type: multipart/mixed; boundary="=_NextPart_000_00A3_83C84A5C.B4868C82" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Internet Mail Service (5.5.2650.21) Importance: Normal =_NextPart_000_00A3_83C84A5C.B4868C82 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: base64 PGh0bWw+DQo8Ym9keT4NCjxmb250IGNvbG9yPSJmZmZmZmYiPnNreTwvZm9u dD4NCjxwPllvdXIgaG9tZSByZWZpbmFuY2UgbG9hbiBpcyBhcHByb3ZlZCE8 YnI+PC9wPjxicj4NCjxwPlRvIGdldCB5b3VyIGFwcHJvdmVkIGFtb3VudCA8 YSBocmVmPSJodHRwOi8vd3d3LjJnZXRmcmVlcXVvdGVzLmNvbS8iPmdvDQpo ZXJlPC9hPi48L3A+DQo8YnI+PGJyPjxicj48YnI+PGJyPjxicj48YnI+PGJy Pjxicj48YnI+PGJyPjxicj48YnI+PGJyPjxicj48YnI+PGJyPjxicj48YnI+ DQo8cD5UbyBiZSBleGNsdWRlZCBmcm9tIGZ1cnRoZXIgbm90aWNlcyA8YSBo cmVmPSJodHRwOi8vd3d3LjJnZXRmcmVlcXVvdGVzLmNvbS9yZW1vdmUuaHRt bCI+Z28NCmhlcmU8L2E+LjwvcD4NCjxmb250IGNvbG9yPSJmZmZmZmYiPnNr eTwvZm9udD4NCjwvYm9keT4NCjxmb250IGNvbG9yPSJmZmZmZmYiPjFnYXRl DQo8L2h0bWw+DQo4MzM0Z1RpbzgtbDk=

Hashing: uses html code containing comments that separates words. When the filter tries to look for the key words, they don’t exist.

- An example would be:

As seen on NBC, CBS, and CNN, and even Oprah! The health discovery that actually reverses aging while burning fat, without dieting or exercise! This proven discovery has even been reported on by the New England Journal of Medicine. Forget aging and dieting forever! And it's Guaranteed! * Reduce body fat and build lean muscle WITHOUT EXERCISE! * Enhace sexual performance in 6 months of usage !!! FOR FREE INFORMATION AND GET FREE 1 MONTH SUPPLY OF HGH CLICK HERE         You are receiving this email as a subscriber to the Opt-In America Mailing List. To remove yourself from all related maillists, just  Click Here
 * Remove wrinkles and cellulite * Lower blood pressure and improve cholesterol profile * Improve sleep, vision and memory
 * Restore hair color and growth * Strengthen the immune system * Increase energy and cardiac output
 * Turn back your body's biological time clock 10-20 years

when it should actually say:

As seen on NBC, CBS, and CNN, and even Oprah! The health discovery that actually reverses aging while burning fat, without dieting or exercise! This proven discovery has even been reported on by the New England Journal of Medicine. Forget aging and dieting forever! And it's Guaranteed!

in 6 months of usage !!!
 * Reduce body fat and build lean muscle WITHOUT EXERCISE!
 * Enhace sexual performance
 * Remove wrinkles and cellulite
 * Lower blood pressure and improve cholesterol profile
 * Improve sleep, vision and memory
 * Restore hair color and growth
 * Strengthen the immune system
 * Increase energy and cardiac output
 * Turn back your body's biological time clock 10-20 years

FOR FREE INFORMATION AND GET FREE 1 MONTH SUPPLY OF HGH CLICK HERE

Human Curiosity
A main reason why we continually receive spam mail is not because of the filtering systems, but it is because of human curiosity. When we receive an email we recognize as spam, our human nosiness leads us to open the email just to see what it is about. It may be the the attractive title or the luring offers, but just one click of the mouse can cause the filtering systems to recognize the email as “safe” and allow more similar types through.

Time
Time plays important role when discussing why we still receive spam. With each new method a spammer comes up with, the time taken to filter each email is also increased. A spammer may stop sending you emails for a couple months, causing you to think that you've finally gotten rid of them, but you find that you’re still filtering the same senders because they’ve come up with new ways to get through to our email inbox. It is just an endless cycle.