Plain english information about computer viruses.
This write-up is oriented toward the novice computer user. More experienced computer
users should skim over the sections they are already familiar with.
If you are clueless about what computer files are, don't despair. As you use your computer, and read
information like that found here, you will come to understand this subject.
Operating System. This write-up describes
viruses with Microsoft Windows, which most people are using. If you are using a Mac, OS/2,
UNIX or other system, the information here will be helpful, but you should consult with an expert
on these other systems.
Quick links to topics below
Viruses are often received from a trusted person.
Different types of attached files.
File naming conventions.
How the virus gets activated.
Spotting emails that contain attachments.
How to determine the file type of attachment.
What an activated virus does to your computer.
How a virus copies itself to others.
How to make your system more secure.
The most devious aspect of most virus attachments, is that
they are often received from a trusted person. A virus that is activated on your system will
usually try to email out copies. Email addresses are picked from a couple different means.
The most common picking method is from your email address book. Another method to pick out
email names of everyone is from in your 'In Box', and there are other means for the virus to find email addresses. Since the person who receives the infected email from you probably knows you, they
figure you to be a trustable source, and they then activate the email attachment which infects
their system.
Different types of attached files. Receiving
an attached data file is not usually dangerous, but receiving an attached program file is very
dangerous.
Shortly after most people begin using a computer, they realize that different types of files
contain different types of information. For example, a Microsoft Word
document file contains information that you have typed, and information about formatting and page
layout. A Quicken file contains the financial data that you have entered in. A picture file
contains information about which colored dot to place where on the screen. Any file containing
information you have entered into your computer is known as a data file.
There are other types of files that are known as program files. Most users have installed
some program on their computer, this installation places program files into their system. These
program files contain instructions for displaying things that are typed, or calculating numbers, or
perhaps how to display picture data on the screen. These program files can also contain
instructions for moving or deleting files from your computer.
File naming conventions. It has become standard
computer industry practice to make the last couple letters of a file name according to what type
of file it is. In Microsoft Windows computers, these last letters are seperated with a period
in the filename followed by usually 3 letters, and are known as the extension.
For example, I typed up a letter in Microsoft Word and saved it as 'quiknote'. The file was
actually saved to my disk with the filename 'quiknote.doc'. Note that the last three letters
after the dot are 'doc' indicating this file has Microsoft Word Document data. Likewise, I created
a picture drawing using the program 'Paintbrush', the file saved with the filename 'quikpic.bmp'.
Note that the extension for this filename is '.bmp' indicating the file is a bitmap picture file.
My favorite game I play on the computer is a card solitare game named 'Arachnid'. If I were to
make a copy to a floppy disk, I would copy the file named 'Arachnid.exe'. Note that the
extension for this filename is '.exe' indicating the file contains executable program information.
How the virus gets activated. Since the
filename extension (the last letters after the last dot) indicate the type of file, your computer
is smart enough to know what to do with the file if activated. Files are frequently represented
by some type of icon, and can be activated by clicking, or double-clicking on it. This includes
icons on your desktop, icons in your start menu, and sometimes as an icon within an email.
If the activated file is a data file (for example a Word Document), then your computer will
start the program and display the data. If the activated file is a program, then the program
simply runs.
Spotting emails that contain attachments.
How to determine the file type of attachment.
What an activated virus does to your computer.
How a virus copies itself to others.
How to make your system more secure.
Symantec Security Check
The Ten Immutable Laws of Security
As borrored from a
Microsoft Technet page.
- Law #1: If a bad guy can persuade you to run his program on your computer, it’s not your computer anymore.
- Law #2: If a bad guy can alter the operating system on your computer, it’s not your computer anymore.
- Law #3: If a bad guy has unrestricted physical access to your computer, it’s not your computer anymore.
- Law #4: If you allow a bad guy to upload programs to your web site, it’s not your web site any more.
- Law #5: Weak passwords trump strong security.
- Law #6: A machine is only as secure as the administrator is trustworthy.
- Law #7: Encrypted data is only as secure as the decryption key.
- Law #8: An out of date virus scanner is only marginally better than no virus scanner at all.
- Law #9: Absolute anonymity isn't practical, in real life or on the web.
- Law #10: Technology is not a panacea.
An old Microsoft joke
As borrored from a
Windows 2000 magazine forum page, posted by Ralph S. Thomas.
A helicopter pilot is lost in a fog over Redmond, Washington, and is struggling to find his
bearings so he can make a safe landing. The pilot asks his passenger to look out for landmarks
or obstacles. Just then, the passenger indicates a tall building with an open window, and the
pilot flies over to it. Seeing someone sitting at a desk by the window, the pilot yells: "Hey!
I'm lost! Can you tell me where I am?"
The person in the window replies, "You're in a helicopter!"
The pilot responds, "Thanks!" Briskly, the pilot then pivots the helicopter 94 degrees to
the east, travels through the fog exactly 1.3 miles, and sets the helicopter down in the center
of the Redmond Municpal Airport's helipad.
The passenger exclaims to the pilot: "Amazing! How on earth did you manage to land this
thing so precisely, without knowing where you were? That jerk in the window was absolutely
no help whatsoever!"
The pilot responded, "That's not true: he was tremendously helpful."
"How?!" the passenger asked.
"He was a Microsoft employee in the Microsoft building: his answer was technically correct,
but totally useless to anyone else who didn't already know how to use that information."
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