LECTURE NOTES ON Spam of Email · Types of Spam Dr. Samaher Hussein Ali Notes of Lecture 12 3. Health and medicine: This category includes advertisements for weight loss, skin care,

College of Information Technology, University of Babylon, Iraq

[email protected]

By

Dr. Samaher Hussein Ali

LECTURE NOTES ON Spam of Email

Department of Software The University of Babylon

14 December 2013

Def. of Spam

Spam messages are the misuse of electronic messaging systems (including most of the media , and digital communication systems ) to send a huge amount of unwanted messages randomly . Although the figure known for messages spam is e-mail (which is what I will talk about in this article ) , but this term is present in other media such as letters of mobile phones , spam blogs, spamming wikis, spam online forums , fax spam . Known spam messages to e-mail other names : write propaganda unwanted ((unsolicited bulk Email (UBE) or junk mail)), or commercial electronic messages unwanted (unsolicited commercial email (UCE).

Note 1:

One of the biggest problems facing the technology e-mail is spam known as "spam" , which constitute 70 to 80% of the total e-mails sent .

Dr. Samaher Hussein Ali Notes of Lecture 12

14 December 2013

The Problem of Spam

Spamming is the scourge of electronic-mail and newsgroups on the Internet. It can seriously interfere with the operation of public services, to say nothing of the effect it may have on any individual's e-mail mail system. ... Spammers are, in effect, taking resources away from users and service suppliers without compensation and without authorization.“

Why All the Fuss? Loss of Productivity.

Discouraged Users. Loss of Efficiency. Legal Issues. Communications Quality. Business Continuity. Company Reputation.

Dr. Samaher Hussein Ali

Notes of Lecture 12 14 December 2013

Types of Spam


Note 2:

the fact that most senders of spam infiltrate the computers of Internet

users and malicious programs they download it (zombies) and use

them to send their messages annoying in huge quantitie.

The main Types of Spam: 1. Propaganda :- More types of SPAM e-mails are propaganda, experience has

shown that the senders of spam targeting certain goods and services to

promote them. Some goods were chosen because computer users might be

interested in them, but most of these goods will be on the black market (such

as prescription drugs are unauthorized). Spam is considered illegal not only

because its goals propaganda but because the goods and services offered by a

legal violation in itself.

2. Fraudulent :- such as messages, which claims the owner that the recipient

can get a share of the funds was not able to sender obtained by himself for

reasons of judicial versus assist the recipient in the legislation of these funds,

and asks the recipient to provide details of his account banking, and of course

if offered the recipient of this details will be stealing his own account, called

this type of message to scam)).

14 December 2013

Types of Spam


3. Health and medicine: This category includes advertisements for weight loss,

skin care, and treatment of baldness, dietary supplements and drugs that may

be unauthorized, and so on, which can be purchased via the Internet.

4. Technology(IT): This category includes offers hardware and software at

discounted prices, as well as services to the owners of sites on the Internet

such as web hosting, domain registration, and improve the sites, and so on.

5. Personal finance: This type of insurance offers, and services to reduce debt,

and loans with low interest rates, and so on.

6. Education and training: This category includes offers for seminars, training,

and access to educational certificates via the Internet and this may be a false

certification

7. Political spam : This category includes mudslinging or political threats from

extremists and possible terrorists. Though these are merely nuisance messages

to end users, security and law enforcement officials need to be aware of such

mailings, since they can provide clues to genuine potential threats, or may be

actual communication between terrorists.

14 December 2013

Rate each Type of Spam Messages


To produce 13%

Trade 22%

Fraud 7%

Health 10%

Net 9%

Entertainment 6%

Religious 5%

The other 25%

Second Def. of spam (n): Unsolicited e-mail, often of a commercial nature, sent

indiscriminately to multiple mailing lists, individuals, or newsgroups; junk e-

mail.

14 December 2013

The Spam Threat

Dr. Samaher Hussein Ali Notes of Lecture 12 14 December 2013

• Users don’t want spam

Lost productivity

Offensive, Embarrassing

Legitimate messages get lost in the sea of spam

• Spam isn’t going away

People buy from spammers

Legislation has not been effective

The SMTP protocol is inadequate

It allows spammers to forge message information

• Spam is difficult to detect

Spammers learn how to get past filters

Legitimate messages WILL be lost

• Anti-Spam is difficult to support

Users don’t like misclassifications

Client based anti-spam solutions interfere

Authorized mass-mailers want special treatment

• Spammers use malware

Viruses “spam” themselves in mass quantities

Compromised computers DoS attack Anti-Spam services (RBLs)

Compromised computers send spam from inside the network

The Disadvantages of Spam


1. According to a study conducted by Nucleus Research in 2009 , cost

management process spam messages American companies more than 71 billion

dollars a year because of the cost of lost production hours at a rate of $ 712 per

employee . physical damage to the annoying messages can be summarized in

the following points:

2. causing wasted staff time , because users who do not have protection against

spam messages Sédron a lot of time to check their messages and delete spam

messages from them.

3. the possibility that the user accidentally deletes an important message because

of the mixing of spam messages with important messages .

4. spam messages cause the waste of network resources , particularly e-mail

server , such as viruses causing it to fill in the database.

5. senders of spam usually infiltrate the computers of users and spam messages

they send them without their permission (Session hijacking).

How can we avoid the Spam Message?


1. Two email addresses. You should use your private address for personal

correspondence only. The public address should be the one you use to register on

public forums, in chat rooms, to subscribe to mailing lists etc.

2. Never publish your private address on publicly accessible resources.

3. Your private address should be difficult to spoof. Spammers use combinations of

obvious names, words and numbers to build possible addresses. Your private

address should not simply be your first and last name. Be creative and

personalize your email address

4. If you have to publish your private address electronically, mask it to avoid

having it harvested by spammers. [email protected] is easy to harvest, as is

Joe.Smith at yahoo.com. Try writing Joe-dot-Smith-at-yahoo-dot-com instead. If you

need to publish your private address on a website, do this as a graphics file rather

than as a link.

14 December 2013

How can we avoid the Spam Message?


5. Treat your public address as a temporary one. Chances are high that spammers

will harvest your public address fairly quickly. Don't be afraid to change it often.

6. Always use your public address to register in forums and chatrooms and to

subscribe to mailing lists and promotions. You might even consider using a

number of public addresses in order to trace which services are selling addresses

to spammers.

7. Never respond to spam. Most spammers verify receipt and log responses. The

more you respond, the more spam you will receive

8. If your private address is discovered by spammers - change it. This can be

inconvenient, but changing your email address does help you to avoid spam - at

least for a while!.

9. Do not click on ‘unsubscribe’ links from questionable sources. Spammers send

fake unsubscribe letters in an attempt to collect active addresses. You certainly

don't want to have your address tagged as ‘active’ as it will just increase the

amount of spam that you receive.

14 December 2013

How can we Reduce the Spam Message?


Spammers are very resourceful and will find a way to get their messages to you. The

only way to really eliminate spam is to use expensive custom anti-spam services like

the ones used in large corporate spam firewalls. Given the ingenuity of spammers

that may not last for long either.

Here, the main significant methods to reduce spam.

1. Remove all clear text email addresses from your website.

2. Make sure your computer is secure

3. Mark all junk emails as junk.

4. Secure all web forms with captcha. Captcha is that wierd box with those hard

to read letters. It is there because computers can't make sense of that image and

people can. This stops robots from filling out online forms and clogging your

inbox. Some industrious spammers will actually pay people to manually fill out

online forms but it is a very small percentage of the total spam.

5. Don't forward chain letters.

6. Don't reply to spam

7. Watch out for check boxes that are already selected.

8. Turn off read and delivery receipts and automatic processing of meeting

requests

9. Block pictures in HTML messages that spammers use as Web beacons

14 December 2013

As a result,


Third def. of Spam is flooding the Internet with many copies of the same message,

in an attempt to force the message on people who would not otherwise choose to

receive it. Most spam is commercial advertising, often for dubious products, get-rich-

quick schemes, or quasi-legal services. Spam costs the sender very little to send --

most of the costs are paid for by the recipient or the carriers rather than by the sender

Spam filter is a program that is used to detect unsolicited and unwanted email and

prevent those messages from getting to a user's inbox.

The Anti-Spam SMTP Proxy (ASSP) server project is an Open Source, Perl

based, platform-independent transparent SMTP proxy server available at

SourceForge.net that leverages numerous methodologies and technologies to both

rigidly and adaptively identify e-mail spam. ASSP is easy to set up because it

requires only minor changes to the configuration of your Mail Transfer Agent

14 December 2013

Anti-Spam Technologies


Although some spam will inevitably get through, a spam slammer -- otherwise known

as a spam blocker or anti-spam, etc -- saves an enormous amount of time that we

would otherwise spend in sifting out the junk by doing this manually.

Generally, anti-spam techniques fall into four categories:

1. Filters

2. Sender Policy Framework (SPF)/Reverse Lookup

3. Challenge/Response

4. Cryptography

Note 3:

In this lecture, we discuss the main steps of Filtering Process:

14 December 2013

Filtering Process


Emails are processed in five phases:

1. Initialization

Email client receives email, forwards it to Spamato, and waits for check result.

2. Pre-Check

Veto against further processing (Configuration, Sender-whitelist)

Gain information for other plugins (URL extractor) Spamato Base

Filter 1

PreCheck(msg)

Checkpoint PreCheck

veto(msg) = veto1(msg) || veto2(msg) || … || vetoN(msg)

Filter 2

PreCheck(msg)

Filter N

PreCheck(msg)

veto1(msg) veto2(msg) vetoN(msg)

. . . . .

Decision

isSpam(msg) = globalDecision(isSpam1(msg), isSpam2(msg), …, isSpamN(msg))

Post Check

Filter1

Filter2

.

.

.

FilterN

msg msg msg

isSpam1(msg) isSpam2(msg) isSpamN(msg)

isSpam(msg)

msg msg msg

Filter 1

Check(msg)

Filter 2

Check(msg)

Filter N

Check(msg)

isSpam(msg)

veto(msg) == true

ignore this msg

. . . . .

msg isSpam(msg)

14 December 2013

Filtering Process


3. Check Each filter calculates the spam probability

4. Decision

The overall spam probability is calculated and returned to the email client

Filtering Process


5. Post-Check

Learn from global decision

Collect statistics

Note 4:

In general, we can split the types of spam filtering into three groups:

1. First group, filter related to list base

Black list

White list

Gray list

Black wholly list

2. Second group, filter related to contain base

Word base filter

Heuristic filter

Bayesian Filter

3. Third group, other filter

Respon spam

Filtering Process


14 December 2013

Documents

LECTURE NOTES ON Spam of Email · Types of Spam Dr. Samaher Hussein Ali Notes of Lecture 12 3. Health and medicine: This category includes advertisements for weight loss, skin care,