According to the
definition
given by Whatis.com, a virus is a
program
that, when run, replicates itself. Viruses are usually attached to, or
hidden
inside, harmless-looking files. They may be transmitted by email
attachments or
any kind of removable disk. In order to become infected, you must
have a
program containing a virus installed on your system, and you must run
it's code.
File
Infector Viruses
Boot
Sector Viruses
Macro
Viruses
Worms
and Trojans
Virus
Transmission
Virus
Prevention (General)
Virus
Prevention (Email Specific)
Recovery
According to Symantec,
File Infector viruses attach themselves to any type of executable
program. When
the carrier program is run, the virus code is run as well. Some damage
the
system, and even those that don't can take up so many system resources
that the
system becomes unstable.
Boot Sectors,
according to the
article on viruses found at Whatis.com,
are
viruses that attach themselves to floppy disks or certain parts of the
hard
disk. The system can be run with a boot sector virus on an inserted
floppy or
on the hard disk, but if such a virus is present when the computer
starts up,
it overwrites or damages the Master Boot Record and prevents the
computer from
booting properly.
Macro Viruses,
according to an article
published by Microsoft, are viruses that use a program's own
macro capabilities to damage the document or other parts of the
system.
These are the most common types of viruses, which usually show up by
putting
unwanted words at the bottom of documents, and can be transmitted by
any type
of file that supports macros (such as Word, Excel, Power Point, and
Access
files).
Worms
are files that, like other viruses, duplicate themselves once they
infect a
system. Some kinds of worms can make themselves into email attachments
and
email themselves to everyone in the infected computer's address book
(this is
generally only a problem if you are using a PC-based email program,
like
Outlook. Web-based email programs, like Yahoo and Hotmail, are usually
safe
from worms mailing themselves to your contacts).
Trojans
are harmful codes hidden inside apparently harmless data (like the
Greek
soldiers hidden inside the Trojan horse) or programs that once inside a
system
can take control and do their chosen form of damage. (Some Spyware
and Adware program also use Trojans).
Only executable
programs can
carry viruses. Viruses can be transmitted by infected disks, by email
attachments, by downloaded programs, by downloaded files that are
disguised to
look like harmless media files, and by infected files that support
macros.
§
Have good virus software, learn to
use it, and
update it as often as the manufacturer recommends. Many types
of
software can quietly run in the background, scanning your system
constantly for
virus-like activity and updating their virus definitions as soon as new
ones
become available. Running the software like this provides maximum
protection,
but NO ANTI-VIRUS SOFTWARE IS PERFECT. Anti-virus
software is
like smoke detectors and the fire department. They let you know if
there is a
problem and fix it, but preventing the problem in the first place is
better.
§
Keep your system patched.
Download
and apply all security-based patches and updates from your software
manufacturer as soon as they become available.
§
Configure your system to display all
file extensions,
including those of known file types. This will help you know
what files
are executable and likely to contain viruses. Click here for how to do this and a
list of
executable file extensions.
§
Especially if you use PC-based email
programs,
make sure it and other parts of your system are NOT set up to
automatically
open attachments or run code. Set the default for VBS (visual
basic
scripting) and JS/JSE (JavaScript) to "edit." This opens code files
in notepad instead of running them. If you really want to open the
file, you
can right click on it and select "open."
§
Scan every file you let onto your
system. This
is especially true of software, even shrink-wrapped manufacturer
software.
§
Learn what the Internet Security
Settings on your
PC do, and set them so you'll get the level of protection you want.
§
Set your Word, Excel, and other
Microsoft Office
program security settings so you get the protection level you
need. Use
Medium if you have to use macros made by other people, high if you
don't have
to use macros made by other people, or disable macro support entirely
if you
don't use macros at all. This will warn you about macros so you can
disable
them if you choose, automatically disable unsigned macros
(respectively), or
not let any macros run.
§
Learn what Active X controls in
Internet Security
settings do and set them so you'll get the protection level you want (these
settings can also prevent pop-up adds). Some sites, like your bank, may
need
you to have these controls enabled. Simply add these to your trusted
sites and
their codes will run, while no other ones will.
§
Don't start your computer with a disk
in the
drive, and avoid saving things downloaded from the Internet on
disks. This
will help prevent boot-sector viruses.
§
Use RTF formats in your own Office
software, and
ask friends to send attachments to you in RTF format. RTF
does not support macros.
§
Consider using a rebel web browser,
such as
Mozilla (which is also free, by the way). These browsers are
often a
lot harder for virus programmers to take advantage of then IE.
§
NEVER open an email attachment sent
from someone
you don't know. Throw it away and empty your trash.
§
NEVER open a forwarded attachment,
even one sent
from someone you do know. These could be worms. Throw them
away and
empty your trash. If you think the sender meant to send the file to
you, ask
him or her to send it to you again in a new message.
§
Check on attachments. If you
get an
attachment from someone you know, before opening it, check with him or
her to
make sure that person sent you the attachment on purpose. If he or she
did, it
might still be infected. Scan it. If it's a media (picture or sound)
file, use
the helper application to open it (windows does not require the use of
the
correct file extensions and viruses can hide in what look like data
files). If
the helper application can't open the file, it may be a virus file.
What if, despite doing all these things,
your computer
gets sick anyway? Here again, planning ahead is the best medicine.
§
Create and keep a bootable
floppy. This
will restore your computer's ability to boot if you get hit by a boot
sector
virus.
§
Backup your data. Save
your most
important information on a removable storage device, like a floppy, CD,
memory
stick, Zip drive, or Flash drive, so you won't loose everything if a
virus
crashes your computer.
§
Retain the install disks of your
operating system
and vital programs. Then you can always reformat
your hard
drive and re-install your stuff if you have to.
§
Ditch Bill Gates. Consider
switching to a
Macintosh or, even better, Linux-based system. Linux systems can run on
PC-compatable systems, are often easy to use, and are almost always
much harder
to hack then Microsoft. There is also a boatload of free Linux software
out
there, everything from operating systems to free graphics software.
There's
also Open Office, a free
Office
software suite that lets you save in Windows-compatable file formats.
It
doesn't get much better then that.