Virus |
What da heck is
Virus? |
Netbus |
A dangerous
virus |
Happy99 |
A top dangerous
virus |
Protection |
Utilities to protect
yourself
|
|

A virus is a
piece of programming code inserted into other
programming to cause some unexpected and,
for the victim, usually undesirable event.
Viruses can be transmitted by downloading
programming from
other sites or be present on a diskette. The
source of the file you're downloading or of a
diskette you've
received is often unaware of the virus. The virus
lies dormant until circumstances cause its code
to be
executed by the computer. Some viruses are
playful in intent and effect ("Happy
Birthday, Ludwig!") and
some can be quite harmful, erasing data or
causing your hard disk to require reformatting.
Generally, there are three main classes of
viruses:
File infectors. These viruses
attach themselves to program files, usually
selected .COM or .EXE files. Some can infect any
program for which execution is requested,
including .SYS, .OVL, .PRG, and .MNU files. When
the program is loaded, the
virus is loaded as well.
System or boot-record infectors.
These viruses infect executable code found in
certain system areas on a disk. They attach
to the DOS boot sector on diskettes or the Master
Boot Record on hard disks. A typical scenario
(familiar to the author) is to
receive a diskette from an innocent source that
contains a boot disk virus. When your operating
system is running, files on the
diskette can be read without triggering the boot
disk virus. However, if you leave the diskette in
the drive, and then turn the
computer off or reload the operating system, the
computer will look first in your A drive, find
the diskette with its boot disk
virus, load it, and make it temporarily
impossible to use your hard disk. (Allow several
days for recovery.) This is why you
should make sure you have a bootable floppy.
Macro viruses. These are among
the most common viruses, and they tend to do the
least damage. Macro viruses infect your
Microsoft Word application and typically insert
unwanted words or phrases.
The best protection against a virus is to know
the origin of each program or file you load into
your computer. Since this is
difficult, you can buy anti-virus software that
typically checks all of your files periodically
and can remove any viruses that are
found. From time to time, you may get an e-mail
message warning of a new virus. Chances are good
that the warning is a virus
hoax.
|