2. What is a computer virus
1. An infective agent that typically consists of a
nucleic acid molecule in a protein coat, is too
small to be seen by light microscopy, and is able
to multiply only within the living cells of a host.
"the hepatitis B virus"
an infection or disease caused by a virus.
"I've had a virus"
a harmful or corrupting influence.
"the virus of cruelty that is latent in all human
beings"
2. A piece of code which is capable of copying
3. Signs of a virus
If you're conversant with computer code,
looking at the actual strings of code in a
suspect program can help spot suspicious or
out of place commands. But even if you don't
know your way around codes it may help to look
at the contents of a data file anyway. Strange
messages are commonly inserted by virus
writers and can be read within the code. Look
at a data file with a word processing program
and search for these.
4. • Applications that don't work properly.
• Disks can't be accessed.
• Printing doesn't work correctly.
• Pull-down menus are distorted.
• File size changes for no apparent reason.
• Date of last access does not match date of
last use.
• An increase in the number of files on the
system when nothing has been added
• Uncommanded disk drive activity.
• Unusual error messages.
• System slows down, freezes or crashes.
5. Signs of a virus conduit
Conduit is normally downloaded along with
software bundles, torrents, freeware,
and shareware as a third party add-on,
extension, toolbar, or plugin. You can also
knowingly download the Conduit
Community Toolbar for your browser
without realizing that it is harmful.
Malicious software developers distribute
their products with Conduit tools
6. Damage caused by computer virus
Computer virus can do something more than what you think.
Every single document that has been stored in the hard drive
will lost forever if you don’t free your system of virus. Losing
personal information is a nightmare and it can ruin a project or
your entire effort in just a few a minute. You can buy a new
computer, but it is quite impossible to get back all those
important documents once they are lost from the system.
A few people believe that using antivirus is not a mandatory
task when you are using a PC. However, they must remember
that total system failure is another issue and most of the time
virus seems responsible for this incident. It can happen to
both PCs and several desktops as well.
7. General types of virus
Boot virus
Program virus
Multipartite virus
Stealth virus
Polymorphic virus
Macro virus
Active x virus
8. Boot virus
Since nobody uses floppy disks anymore, these
types of computer virus are left to infect only
the master boot records of the hard disk. The
boot record program loads the operating
system in the memory at startup. These
viruses replace the boot record and move it to
a different part of the hard disk, or simply
overwrite it. As you can imagine, once you
start your operating system, it loads into
memory, along with the virus. Once the virus is
in the memory, it is free to do whatever it was
9. Program viruses
These types of computer virus will
infect only executable files (with
extensions like .BIN, .COM, .EXE, .OVL, .DRV, and
.SYS). Once executed, these programs load
into memory, along with the virus
contained within them. Once in the
memory, the scenario repeats – the virus
is free to act and infect other files or
10. Multipartite viruses
These computer viruses are hybrids,
derived from boot viruses and
program viruses. They infect
executable files, just like the
program viruses but, once the
executable is executed, it infects
the master boot records. The
scenario is similar to the boot virus’s
11. Stealth viruses
These viruses are specialized in
avoiding detection and will use a
number of techniques to do so. Most
of them simply redirect the hard
disk head, forcing it to read another
memory sector instead of their own.
Some of them also alter the reading
of the file size shown when listing
12. Polymorphic viruses
The polymorphic viruses will
always change their source
code from one infection to
another. Each infection is
different, and this makes
detection very hard. However,
detection is still possible,
13. Macro viruses
This virus is relatively new and it
infects macros within a template or
document. When you open a word
processing document, it activates the
virus. The virus infects the
Normal.dot template, which is a
general file used by all the
documents. So, whenever you open an
14. Active X viruses
Most people do not know how to
configure ActiveX and Java
controls, unconsciously leaving a
security hole. Applets are then
allowed to run freely on the
machine, delivering all ActiveX
viruses. By simply turning off
15. Anti- virus
Antivirus software is a computer
program that detects, prevents,
and takes action to disarm or
remove malicious software
programs, such as viruses and
worms. You can help protect your
computer against viruses by using
antivirus software, such as
