Why forward emails? Why worry about opening attachments? And what is a virus? These questions and more are covered in this short presentation.

1. Avoiding Email viruses

2. What is a virus?
Viruses are, by definition, small infections that
replicate inside the cells of a living organism.
Like their predecessors, a computer virus is a
program which can replicate itself and then
spread from one computer to another.
Sometimes, malware, adware and spyware are
called viruses, although they cannot replicate
themselves. Instead, they can exploit the
security of the computer as well as computers
within their network.
Some viruses can harm a computer’s data or
performance, but many are harmless.

3. Why are viruses
created?
We all dread the knowledge that our
computer may be infected with a
virus. But why would anyone go
to the trouble and expense of
creating one? There are many
reasons why a computer virus
may be created. Here are some of
them…

4. 1. To Control the
computer
This enables the creator of the virus to
attack web servers by having each
infected computer sent information to the
server, thus overloading the system, and
shutting down the server (which may
host a rival website). It can also be used
to send spam to infected computers.

5. 2. To generate money
The virus may pretend to offer free
spyware or virus removal tools. Once
installed, they will “scan” your computer
and find all sorts of viruses that they will
remove, provided you pay for the full
version of the application.

6. 3. To steal your
information
They may actually be able to keep
track of everything you type on the
keyboard, thus providing access to
your passwords, account numbers
and personal information.

7. 4. Just because they
can
Yes, some people would stoop this low
to deliver a message, such as a virus
which would cause your computer to
restart with the message: “billy gates
why do you make this possible? Stop
making money and fix your software!”
(actual virus!)

8. 5. To shut down a
computer or network
Although viruses that shut down a
computer are not as common as they
once were, viruses to shut down a
network are very common. Known as a
DNS (denial of service), they will cause a
excess amount of activity on a network,
shutting it down eventually.

9. Email and viruses
One of the most prevalent ways to
spread a virus is by using Email.
Although most of us use Email on a
daily basis, many of us are naïve of
the consequences of a “bad” Email.
Let’s look at some of the ways that
viruses are spread by Email.

10. 1. A Virus as an Email
Hoax
Although not the worse thing that can
happen, an email may contain false
information (a child needing an organ
transplant or a virus warning). This will
not infect your computer, but can clog up
the email servers of the recipients,
making it a waste of time, resources and
energy. To read more about email
hoaxes, see Hoax-Slayer.

11. 2. In an Email
attachment
This is a clear reason why you don’t open
attachments if you are not sure who sent them, or if
they are authentic. These attachments can contain
viruses which run programs, or infect programs on
your computer (such as Word or Excel). The harm
only occurs if you open the attachment, so if you are
unsure, delete the email. Caution: If your contacts
have been affected by a virus, they may be sending
you a rogue infection without you knowing. In this
case, to be safe, save the attachment to your hard
drive, and then scan it with your virus scanner.

12. 3. In the body of the
Email
It is now possible to place a virus right into the
e-mail. In this case, the virus will be
automatically triggered when you open the
email. This is done by embedding the message
into the email. You will usually see a warning
asking you to click if you want to see embedded
information. Only do this if you are certain of
the source. Also, be wary of URLS (links to a
web page) which may actually link you to a site
where a virus will be downloaded. If you are not
certain of the sender, don’t open URLS in your
email.

13. Summary
• Verify the source of any suspicious email
before you open it
• Do not blindly forward e-mail
• Do not open attachments or links unless you
are certain of the sender
• Use caution when authorizing your computer
to display content of trustworthy sources
• Make sure that your email program does not
automatically download and open
attachments or display HTML content
(embedded)

14. Resources
Click on these links for more information
• Top Ways People Get Infected by an Email
Virus
• Why do People Create Computer Viruses?
• Top Ten Best Free Anti-Virus Programs
• Top Five Current Email Scams You Should
Know About

15. For more information:
Contact me: mprine@sdccd.edu