This document discusses various types of malware including viruses, worms, Trojan horses, and spam. It defines each type and provides examples. Viruses are programs that replicate themselves and can damage computer systems. Different types of viruses are described. Worms replicate rapidly across networks to infect other systems through security vulnerabilities. Trojan horses disguise harmful programs as legitimate files. Spam is defined as unsolicited commercial email. Methods of prevention for each type of malware are mentioned.

1. iruses orms
rojans
& and Other Info-Tech Diseas
by: Rafeth Ahmed
Nitish Baghla

2. table of content
1. Computer abuse 4. Trojan horses, worms
a) What is computer abuse… a) Worms
b) Trojan Horses
2. Spam
a) What is spam? 5. Summary and conclusions
b) How does spam work?
c) How’d they get my email? 6. References
d) Spam prevention
3. Viruses
a) Computer Viruses
b) History of viruses
c) History of virus continued…
d) Types of viruses
e) Virus effects…
f) Virus process and cycle
g) Top 10 virus attacks and cost
h) Virus prevention
i) Why do we have viruses?

3. Is This Computer
abuse?
1
 or is it more like this?
2

4. abuse…
"The unauthorized use of, or access to, a computer for
purposes contrary to the wishes of the owner of the computer
or the data held thereon.” 3
Such as:
 Hacking
 Pornography
 Viruses

5. spam ?
no…
…not…
… this kind
4

6. ?
 Spam is all those unwanted advertisement of a company
or their products distributed online.
 Most spams are delivered via emails.
 To avoid being spammed companies do have filters, but
the best we can do is just ignore the emails and delete
them.
5

7. how does
spam work ?
Filter Bypass
Paid E-mail
Junk Mail Humans Spam
Spam
Phishing Commercial Advertising

8. how’d they get
my e-mail ?
6 7
8
9

9. spam prevention
 Don’t give out email addresses to unreliable sources
Spam protection in your computer (most email services
provide spam filtering)
Read carefully when filling out online forms requesting your
e-mail address, and exercise your choice.
Use multiple e-mail addresses.
Short e-mail addresses are easy to guess, and may receive
more spam.
Spam protection from your ISP

10. 12
11
10

11. computer virus
To be defined as a virus, a Virus Components:
program must: The Replication mechanism
 Replicate itself in order to  allows virus to copy itself
carry out a mission.
 Create damage to the
The Protection mechanism
computer system "infected".  Hides virus from detection
The Trigger
Or A virus is a program which  Mechanism which will set off
reproduces itself, hides in the payload
other computer code without
permission and does nasty or The Payload
undesirable things, not  Effect of the virus
intended by its victim. 13

12. viruses…
 Technically, the concept of a  The first virus “in the wild,”
computer virus was first as they say, infected Apple
imagined in 1949, well II floppy disk in 1981. Its
before computers became name was” Elk Cloner”. all it
commonplace. did was display a short
 Von Neumann used his rhyme onscreen:
theories in the 1950s, at Bell
Labs. “It will get on all your disks
It will infiltrate your chips
Yes it’s Cloner!
It will stick to you like glue
It will modify ram too
Send in the Cloner!” 14

13. viruses
continued…
 in 1983 when Fred Cohen, demonstrates a computer virus
during a security seminar at Lehigh University in
Pennsylvania.
 In 1986, the Brain virus became the first documented file
infector virus for MS-DOS computers
15

14. types of viruses
Boot Viruses
 Infect the boot block on a floppy or hard disk
File Viruses
 Infect .EXE or .COM files
Multi-partite Viruses
 Infect both boot blocks and executable files.
Polymorphic Viruses
 Is self-modifying, changes each time it infects a file or disk.
Meta Viruses
 First viruses to infect data files and to work on multiple
platforms. 13

15. virus effects…
 Trivial, simply reproduces or displays messages.
 Minor, alters or deletes infected files.
 Moderate, wipes out entire disk drive.
 Major, slowly corrupts data with pattern, making restoration
difficult.
 Severe, slowly corrupts data without pattern, making
restoration impossible.
 Unlimited, virus which discovers system administrator's
password and mails it to one or more users, tempting them to
use it for illegal purposes
13

16. and cycle
Virus Process
16
Virus Cycle
16

17. top 10 virus
attacks and cost…
Rate Name Year Cost ($ Million)
1 Morris 1998 10 – 100
2 Melissa 1999 60 – 100
3 Love Letter 2000 5.5
4 Code Red 2001 2.6
5 Nimda 2001 635
6 SQL Slammer 2003 750 – 1000
7 MS Blaster 2003 100 – 150
8 MyDoom 2004 250
9 Sasser 2004 120
10 Witty 2004 10 – 30
17

18. prevention
…
There are plenty of companies
dedicated in preventing viruses
from infecting our computers.
They are known as antiviruses or
computer security systems
19
Such as…
18
20

19. why do we have
viruses?
 Why are there so many
new viruses? Is it because
some troll is making it for
fun? Or is it…
 Because antivirus
companies are creating
new ones so we are bound 21
to buy their products?

20. worms
22
no…
23
…not…
… these kinds ?

21. worms
 A worm is a program that scans a company’s network, or the
Internet, for another computer that has a specific security hole. It
copies itself to the new machine (through the security hole),
Understanding Computer Viruses then starts replicating itself there.
 Worms replicate themselves very quickly; a network infected with a
worm can be brought to its knees within a matter of hours. Worms
don’t even have to be delivered via conventional programs; so-called
“fileless” worms are recent additions to the virus scene. While in
operation, these programs exist only in system memory, making
them harder to identify than conventional file-hosted worms.
16

22. trojan horse
 A Trojan horse is a program that claims to do one thing but then
does something totally different. A typical Trojan horse has a
filename that makes you think it’s a harmless type of file; it looks
innocuous enough to be safe to open. But when you run the file, it’s
actually a virus program that proceeds to inflict its damage on your
system.
 It delivers its payload through deception, just like the fabled Trojan
horse of yore. Trojan horses are becoming more common, primarily
through the spread of Internet-based e-mail. These e-mail Trojans
spread as innocent-looking attachments to e-mail messages; when
you click to open the attachment, you launch the virus.
16

23. conclusion
 Well most people believe that all computer threats are due to a
virus, but now we know that there are a lot of different threats
beside viruses
 Such as there are spams, trojans, worms,
 From spams we know there are different sorts, such as phishing
 Back to viruses we learnt a little bit of what it does such as how it
infects our computer system and destroys it slowly.

24. 1.
2.
3.
references
http://thecampbells2000.com/tech/computer-rage-1-jpg640x480.jpg
http://www.youtube.com/watch?v=QEXGPhEVGXo&feature=related
http://www.cyberagentsinc.com/computer_abuse.htm
4. http://f00.inventorspot.com/images/1559606_340_1116081430036-spam.jpg
5. http://www.nolo.com/legal-encyclopedia/how-does-spam-work-30013.html
6. http://d2eosjbgw49cu5.cloudfront.net/mobile-weblog.com/imgname--
amazoncom_launche_wireless_superstore---50226711--images--amazon.com_logo.jpg
7. http://www.grattecenne.com/wp-content/uploads/2009/06/12803_f260.jpg
8. http://globalthoughtz.com/wp-content/uploads/2011/01/Monster_Jobs_Logo1.jpg
9. http://www.gomonews.com/wp-content/uploads/2009/10/wal-mart-logo.jpg
10. http://healyitworks.com/wp-content/uploads/2009/06/virus5.jpg
11. http://www.standrews.k12.nf.ca/Computerwebquest/Computer.JPG
12. http://3.bp.blogspot.com/_98d57p8JHP8/Shgw4c_LsuI/AAAAAAAAAlA/usVdPWwQ87I/s320/ist2_
3199745-computer-virus.jpg
13. http://ksi.cpsc.ucalgary.ca/courses/547-96/cochrane/present/index.html
14. http://media.wiley.com/product_data/excerpt/77/07821412/0782141277-2.pdf
15. http://www.wired.com/thisdayintech/2009/11/1110fred-cohen-first-computer-virus/
16. http://www.pdfking.net/Understanding-Computer-Viruses--PDF.html
17. http://www.itsecurity.com/features/10-worst-virus-attacks-111207/
18. http://community.spiceworks.com/images/products/0001/4741/mcafee_logo.jpg
19. http://3.bp.blogspot.com/-FiNWkEhzD9s/TZMwudIEEVI/AAAAAAAAAp4/ar3IktAg-
D4/s1600/norton-360.gif
20. http://custompc.ca/files/2009/06/press_logo_avg.jpg
21. http://farm3.static.flickr.com/2285/1594411528_724051d57c_o.jpg
22. http://cultofmac.cultofmaccom.netdna-cdn.com/wordpress/wp-content/uploads/trojan_horses.jpg
23. http://gallery.hd.org/_exhibits/natural-science/earth-worm-AJHD.jpg
24. http://www.bloggingfor.info/wp-content/uploads/2010/10/hmmm.jpg

25. thank you
are there
any
question ?
24