Computer virus:
A computer virus is a program which can multiplie and replie itself. There are
also many virus programs which couldn't replie but produce huge damage such as adware
and spyware.
What does a virus do?
A computer virus is as similar to normal virus in terms of power todistructand
replie. A virus attacks main program or changes its function i.e when a program effects with
a virus it does not behave as before and it produces different data which damage other
programs running. This crtes large amount of unwanted programs and disturb computer
important functions. Due to this data gets disloed or damaged and system primary
programs(boot programs,organizingprograms etc)gets disturbed and the computer gets
damaged.
Where does viruses attack, store:
Inorder to get replied,virus should be attached to the which is frequently
executed. In a computer, system programs are those which frequently gets executed and all
which execute will relate to system programs ,hence virusess will be present where
OS(operating system) is installed i.e in many systems it is C: drive. Due to this rson data
present in c: drive gets spoiled quickly than other data in computer.
Types of viruses:
It is one of the strong effecting virus known.
Trojan horses are specially designed by user
to do specific task. It silently gets in to the
program and when executed it does
undesired functions. A Trojan Horse neither
replies nor copies itself, but causes
damage or compromises the security of the
computer. A Trojan Horse must be sent by
someone or carried by another program and
may arrive in the form of a joke program
orsoftware of some sort. The malicious functionality
of a Trojan Horse may be anythingundesirable for a computer user, including data destruction
or compromising a system byproviding a mns for another computer to gain access, thus
bypassing normal accesscontrols.
2.Worms:
A worm is a program that makes and facilitates the distribution
of copies of itself; for example, from one drive to another, or
by copying itself using email or another transport mechanism.
The worm may do damage and compromise the security of the
computer. It may arrive via ation of a system vulnerability
or by clicking on an infected e-mail.
3.Bootsector Virus:
A virus which attaches itself to the boot
programs or the place in hard where boot
sector programs are stored. These are
normally sprd by floppy s.
4.Macro Virus:
Macro viruses are viruses that use another
appliion's macro programming language to
distribute themselves. They infect documents
such as MS Word or MS Excel and are
typically sprd to other similar documents.
5.Memory Resident Viruses:
Memory Resident Viruses reside in a
computers main or primary memory (RAM).
They are initiated from a virus which runs on
the computer and they stay in memory after
it's initiating program closes.
6.Rootkit Virus:
This virus type is erally used by s to
gain control of someone's computer.A rootkit
virus is an undetectable virus which attempts
to allow someone to gain control of a
computer system. The term rootkit comes
from the linux administrator root user. These
viruses are usually installed by trojans and are
normally disguised as operating system files.
7.Polymorphic Viruses:
A polymorphic virus not only replies itself
by crting multiple files of itself, but it also
changes it's digital signature every time it
replies. This makes it difficult for less
sophistied antivirus software to detect.
8.Logic Bombs/Time Bombs:
These are viruses which are programmed to
initiate at a specific date or when a specific
event occurs. Some examples are a virus
which deletes your photos on Halloween, or a
virus which deletes a database table if a
certain employee gets fired.
9.Companion Viruses:
Companion viruses can be considered as a
type of file infector virus, like resident or direct
action types. They are known as companion
viruses because once they get into the system
they ccompany with other files that alrdy
exist and help them to carry there actions
more effectively.These erally use the
same filename and crte a different extension
of it. For example: If there is a file "Me.exe",
thevirus crtes another file named "x.com" and hides in the new file. When the system calls
thefilename "x", the ".com" file gets executed (as ".com" has higher priority than ".exe"), thus
infecting the system.
10.FAT virus:
FAT (file alloion table) is the part of a used to store all
the information about the loion of files, available space,
unusable space, etc. FAT virus attacks the FAT section and
may damage crucial information. It can be especially
dangerous as it prevents access to certain sections of the
where important files are stored. Damage caused can result in loss of information from
individual files or even entire directories.
11.Web Scripting Virus:
Many web pages include complex in
order to inorder to perform somedesired
function .When this is ed or
accessed from system it crtes undesirable
actions.The main sources of web scripting
viruses are the web browsers or infected web
pages.
12.Multipartite Virus:
These viruses sprd in multiple ways possible. It may vary in its action
depending upon the operating system installed and the presence of
certain files.In the initial phase, these viruses tend to hide in the
memory as the memory resident viruses do, then they infect the hard
.
13.Overwrite Viruses:
These type of virus deletes data when effects a file. After its
action the file becomes totally useless. The virus replaces the
file content. However, it does not change the file size.
14.Spyware:
Spyware is software that aids in gathering information about a
person or organization without their knowledge and that may send
such information to another entity without the one notice or that
asserts control over a computer without the consumer's knowledge.
Spyware is mostly classified into four types:
1: system monitors
2: trojans
3: adware
4: tracking cookies
Spyware is mostly used for the purposes such as ; tracking and storing internet
users movements; serving up pop-up ads to internet users.
Whenever spyware is used for malicious purposes, its presence is typically hidden from the
user and can be difficult to detect. Some spyware, such as loggers, may be installed by the
owner of a shared, corporate, or public computer intentionally in order to monitor users.
Source: wikipedia
No comments:
Post a Comment