A virus is an executable program and spread over one computer to
another. But it is a common term and it refers to other types of malware,
computer worms, Trojan horses, spyware, rootkits, adware and other unwanted or
malicious software including true viruses. It has the capability to duplicate
itself and thus continuing to spread. Some of them may harm the computer a bit
while others can bring the severe negative effect which can damage the entire
system.
There are various types of viruses which can be classified in
accordance with their origin, types of files they infect, where they hide,
techniques, the type of operating system, the kind of damage they cause or
platform they attack. We are going to discuss about them in brief:
Memory Resident Virus
These types of viruses stays in the RAM first and execute its
malicious code from there. Then get activated whenever the OS runs and damage
all the files that are then opened. All the Memory Resident Viruses like CMJ,
Meve, Randex, MrKlunky generally corrupt the files and programs that are
opened, closed, renamed, copied etc.
Direct Action Viruses
These viruses are generally found in the hard disk's root directory
and continue to change its location in the new files whenever the code is
executed. FindNext / FindFirst technique is used to attack the files. Direct
Action Viruses such as Vienna virus infects those files and programs in the
directory or folder that are specified in the AUTOEXEC.BAT file path. It also
infects the external devices like hard disks by copying itself on them or pen
drives.
Overwrite Viruses
This type of viruses like Way, Trj.Reboot, Trivial.88.D delete the
information contained in the files that it infects. It replaces the file
content also.
Boot Sector Virus
The Boot Sector Viruses such as Polyboot.B, AntiEXE attack the boot
sector of hard disk. It is a vital part of the disk as the information of the
disk itself is stored along with the program that helps to boot the system.
They are also called Master Boot Record Virus or Master Boot Sector Virus.
Macro Virus
Relax, Melissa.A, Bablas, O97M/Y2K are called as Macro viruses and
they are considered as a type of e-mail virus. These viruses automatically
infect the programs or application that is composed of macros like .pps, .doc,
.mdb, .xls, templates etc.
Cluster Virus/File System Virus
Cluster Virus/File System viruses (also called Directory Virus ) such
as Dir-2 virus etc. attack the directory of the computer system by altering the
path that indicates the location of a file. It infects a program file with an
extension .EXE or .COM. Once infected, it is not possible to locate the
original files.
Polymorphic Virus
Polymorphic viruses encode or encrypt themselves using different
algorithms and encryption keys and all time they attack the system. Elkern,
Marburg, Satan Bug and Tuareg are considered as Polymorphic viruses.
Companion Viruses
Companion viruses are considered like direct action or resident types.
They are known as companion viruses because if they get into the system they
'accompany' the other files that already exist.
These generally use the same file name and create a different extension
of it. For example: If there is a file "ABC.exe", the virus creates
another file named "ABC.com" and hides in the new file. When the
system calls the file name "ABC", the ".com" file gets
executed.Stator, Asimov.1539 and Terrax.1069 are some examples of Companion
Viruses.
FAT Virus
FAT virus such as Link Virus infects the FAT section and may harm important
information. It can be especially harmful as it blocks all accesses to
particular sections of the disk where crucial files are stored. It causes to
loss of information from distinctive files or even entire directories.
Multipartite Virus
Invader, Flip and Tequila are called as Multipartite Viruses and they
infect the hard disk.
Web Scripting Virus
The main sources of web scripting viruses are the infected web pages
or the web browsers .JS.Fortnight is a such type of virus that spreads through
malicious e-mails.
Worms
Worms generally spread through networks and e-mails . They do not
damage files but they duplicate very fast that the entire network may be
disrupted. PSWBugbear.B, Lovgate.F, Trile.C, Sobig.D, Mapson are the examples
of Worms
Trojans
Another severe malicious code is Trojans or Trojan horses that are a
program which pretends itself as a useful application or program . It may cause
to bring the fatal errors in the system.
Computer virus is written with the purpose of invading a computer
without the user’s knowledge or acceptance. Once your computer is infected, it
needs to remove all the malicious functions immediately taking the assistance
of
Online Virus Removal Tech Support. Those efficient technicians will guide you to make safe your
computer from viruses. For any virus Infection Issue call our
Virus Removal Support at +1-877-255-3353.
