Table Of Contents
• Introduction – What is a Virus?
• History of the Virus
• Variants and Forms of Malware
• How to Defend Yourself
Intro – What is a Computer Virus?
• A computer virus is a small software
program that spreads from one computer
to another computer and that interferes
with computer operation.
• A computer virus may corrupt or delete
data on a computer, use an e-mail
program to spread the virus to other
computers, or even delete everything on
the hard disk.
Some Examples of Viruses
• Melissa – considered the first email virus;
released in 1999
• ILOVEU – sent passwords back over the
network and infected machines; written by
a Filipino student in 2000.
• Boot Sector – spread by floppy disks in the
80s and 90s
• Klez – used emails and email address
books to replicate and spread; released in
History of the Virus
• First Virus Created? – The
• The Brain Virus was:
• created in 1986 by two
Pakistani brothers, Amjad
and Basit Farooq Alvi.
• Was spread around by
• Infected boot records
only (not the HDD)
• Cluttered free space on a
floppy making it unusable.
How The Brain Virus Was Spread
• According to a 1988 article in Time
Magazine, a shop called “Brain Computer
Services was selling brand-name
computer programs, such as Lotus 1-2-3
and WordStar ... for as little as $1.50
each.” From 1986-87, many Americans
stopped by their store, purchased these
disks, and brought them back home..
More On “The Brain” Virus
• As Americans loaded these boot-legs programs
from their floppy disk to their computers, “a
snippet of computer code many consider to be
the world's most sophisticated computer virus“
was spread rapidly and infected over 100,000
• Source: Time Magazine (1988) By Philip Elmer-
DeWitt and Ross H. Munro/Lahore Monday,
Sep. 26, 1988 “You Must Be Punished”
More About the “Melissa” Virus
• Written by David L. Smith
in March 1999
• It infected countless
thousands of PCs
(estimated damage = $80
• Replicated by sending
copies of itself to
addresses in the Microsoft
Outlook address book.
• Forced companies like
Microsoft, Intel, and
Lockheed Martin to shut
down their email servers.
• The author is subsequently
jailed for 20 months.
Many Variants of Malware
• Worms – malicious software programs designed
to replicate themselves, find open ports on your
computer, and bottleneck your computer.
• Trojan Horse – malicious software that is
disguised as another application but causes
harm to your computer. It hides itself and then
add a backdoor which can be opened later to
run denial of service (DoS) attacks.
• AdWare – spy programs installed that allows
companies to track your activities on visited
websites (usually without your consent).
Variants of Malware (Cont’d)
• Rootkits – malicious programs that are installed
below the operating system (OS) level. These
programs usually load up during the boot
process (the kernel or “root” level), just before
the OS is fully loaded.
• The “kits” part refers to the different tools
hackers can use to maintain secret access to
your machine once the rootkit is installed.
• NOTE: Not all rootkits are detectable by antivirus or
anti-rootkit programs. If you discover a rootkit on your
machine, experts recommend reinstalling the OS!!
The First Worm?
• Morris Worm
• Written by Cornell student Robert
Tappan Morris in 1988
• Activated the worm from a
computer at MIT
• Found vulnerabilities in Unix and
corrupted thousands of computers
the first day released
• Convicted under the 1986
Computer Fraud and Abuse Act,
sentenced to community service
• Present role: Professor at MIT
Some Well-Known Worms
• Nimda - infected machines via email, web, IIS,
network shares and backdoors; released in 2001
• MyDoom – massive email worm (created 2004)
• SoBig – email worm (variants A – F)
• Code Red and Code Red II – infected thousands
of Windows NT/2000 servers, over $2 billion in
• SQL Slammer – shut down Microsoft’s Outlook
and stopped databases nationwide (Bank of
America to name one) in 2003
• Blaster Worm – a worm that generated buffer
overflow attacks, causing havoc in 2003.
Are Viruses and Worms the Same?
• Viruses are dependent on other programs
to help them spread. They “piggyback” off
existing programs and then execute when
opened by a user.
• Worms can replicate themselves and do
not need to “piggyback” in order to
The First Trojan Horse?
• PC-Write Trojan. According to Kylee Dickey of
Smart Computing Magazine, the first Trojan
horse, PC-Write Trojan, appeared back in 1986.
• It pretended to be version 2.72 of the shareware
word processor, PC-Write. (Quicksoft, the
company that made PC-Write, never released a
• It performed two actions:
1. It wiped out the FAT (file allocation table; system a
PC uses to organize contents on the hard drive)
2. It formatted the hard drive, deleting all saved data.
Some Other Well Known Trojans
• Sub Seven
• Liberty Trojan – In 2000, people thought
that this program was a patch that allowed
PDA users to play Nintendo Game Boy
games on the Palm OS. Instead, it deleted
personal files when opened.
• Storm – This nasty 2006 Trojan program
infected millions, allowing hackers to turn
infected machines into bots.
Adware and Rootkits
• Adware and rootkits can also cause major
problems for computer users in different
AdWare Is A Big Problem
• Every day, thousands of advertisers track
you on every website you visit (via cookies
and other tools) and collect your personal
data without your knowledge.
• Examples of Companies Tracking You:
• Google Analytics
The First Rootkits?
• SunOS rootkit by Lane Davis and Steven
Dake in 1990
• NTRootkit created by Greg Hoglund in
• Sony BMG’s Extended Rights Protection
in 2005 – rootkit from CDs that limited
users’ ability to access their music CDs
• Mebromi – considered the first BIOS
rootkit in the wild
Dealing With Rootkits
• Here are some recommended anti-rootkit tools:
• Kaspersky TDSS Killer
• Hitman Pro
• Rkhunter (Linux based)
• Unhide and unhide.rb (Linux based)
• Recommended Rootkit Removal Guide:
• See Computer Weekly’s Rootkit and Malware Guide:
• Again, if the rootkit can’t be completely
removed, reinstall your OS
How to Defend Yourself?
• Use A Firewall – There are two types:
1. Hardware – some examples are:
• Cisco PIX
2. Software – some examples are:
• Zone Alarm
• Windows Firewall
Using Antivirus Software
• Use Antivirus Software to protect your computer.
• According to Microsoft, less than 30 percent
of all users have up-to-date software on their
machines (including security patches).
• Some Recommended Antivirus Programs
• AVG (by Grisoft)
Use AntiSpyware Programs!
• Spyware is usually hidden in cookies and
in the Windows registry. Some are
dangerous and can hinder performance.
Protect your OS against spyware.
• Some popular AntiSpyware Programs:
• Windows Defender
• Spybot Search & Destroy
• Spyware Blaster
Use Ad Blockers!!
• Take control of your privacy. You can stop
ad networks from snooping on you.
• Here are some adware blockers that are
• DoNotTrackPlus by Abine
• Adware Blocker
• Most web browsers also have a built-in anti-
phishing tool that should be turned on.
Other Virus Prevention Tips
• Educate Yourselves!! – This sounds simple, but
nothing is more important than educating people
on the fundamentals of computer malware
• Update patches for third-party Applications
• Third party apps like Adobe must be updated
regularly to stop newly discovered exploits
• Update patches for the OS (MS and Linux)
• Microsoft Security Updates (available on Patch
Tuesday – second Tuesday each month)