Computer Virus: Definition, Types, and Examples
Definition of Computer Virus
Computer
viruses are almost like flu viruses, they are designed to spread from one host
to another host. And they have the ability to replicate themselves every time
period. But computer viruses cannot reproduce without host cells, it means that
computer viruses cannot reproduce and spread without program such as files or
documents.
And in
technical terms, computer viruses are a type of malicious code or program that written
to change the way computers operate and are designed to spread from one
computer to another. Computer Viruses operate by inserting or attaching
themselves to legitimate programs or documents that support macros to execute
the code. In the process the virus has the potential to cause unexpected or
destructive effects, such as damaging system software by damaging or destroying
data.
How Computer Virus Attack
After the computer
virus has successfully attached to a program, file, or document, the virus will
be inactive until a situation causes the computer or device to execute the
code. In order for a virus to infect your computer, you must run an infected
program, which in turn causes the virus code to run. This means that the virus
can remain inactive on your computer, without showing main songs or symptoms.
However,
once the virus starts infecting your computer, it can also infect other
computers in a network that is connected to your computer. Computer viruses can
do various things on your computer without your knowledge, such as stealing
passwords or data, recording key presses, corrupting files, spamming your email
contacts, and even taking over machines. These are just a few of the
destructive and annoying things that viruses can do.
While some computer
viruses can play around in intentions and effects, others can have profound and
destructive effects, such as deleting data or causing permanent damage to your
hard disk, and worst of all, some are even designed taking into account
financial benefits.
How Computer Viruses Spread
In a world
that is constantly connected today, you can contract a computer virus in many
ways, some more clearly than others. Viruses can be disseminated via e-mail
attachments and text messages, Internet file downloads that contan virus,
social media fraud links, and even your mobile devices and smartphones can be
infected with cellular viruses through shady Application downloads that contain
virus. Viruses can hide it as an attachment of content that can be shared
socially such as funny pictures, greeting cards, or audio and video files.
To avoid
contact with computer viruses, it is important to be careful when surfing the
web, downloading files, and opening links or attachments. As a best practice,
never download text or email attachments that you don't expect, or files from
websites that you don't trust.
How to Protect Against Computer Viruses
As you can
see, like a malignant flu virus, a computer virus is something you want to
avoid. The terms viruses and malware are often used interchangeably. However,
viruses are one of many types of malware, and are only one aspect of the
overall threat landscape.
Therefore,
traditional antivirus software or old versions of antivirus will not be able to
fully protect you from all threats. Because hackers also always create viruses
that are more dangerous and powerful to be able to break into current
protection systems.
Instead,
look at comprehensive security software like these Antivirus. With technology from patented antivirus that works
together to outsmart online threats, scan your system for viruses, and run
automatic silent updates continuously, antiviruses can protect your device from
existing threats.
If the virus
enters through our watch during your subscription period, the antivirus support
experts will do anything to help fix the problem at no additional cost. That is
the guarantee and peace of mind that you only get with the Promise of
Anti-Virus Protection. There are free or paid security software services that
offer this kind of guarantee.
To learn
more about antivirus, you can visit our article about the complete definition, type, and example of an antivirus. So if
you really understand the process or performance of an antivirus, you can
determine which antivirus you think has the best performance.
And we have
several antivirus references that arefree and without ads, even though this antivirus is free, but it is so powerful
to protect your device from various virus attacks.
Types of Computer Virus
What is a
computer virus and types of virus? If we talk about computer security, computer
viruses are the main threat. This viruses can destroy just one program or all
computer systems. The first virus was created in the 1970s and called the
Creeper virus, affecting computers on the ARPANET. In 1981, the first
hacker-made virus appeared and spread through Apple's floppy drive.
According to
the Information Technology Promotion Agency, the number of viruses swelled to
52,151 in 2004. However, due to certain programs that completely eliminate the
virus, the number dropped to around 14,000 in 2010.
What is
computer virus and its types? 57% of the threats that affect the security of
your computer are viruses. There are many computer virus names like computer Trojan,
adware, computer worm, and malware, among others. Now, the virus is still
widespread, affecting PC performance. Viruses are also hacking tools to get
unauthorized access to your system and steal personal information. It is
important for you to know the various types of viruses that affect your
computer.
Computer Viruses List
1. Resident Virus
Resident
viruses live in your RAM. This can interfere with normal system operations
which can cause file and program corruption. The most popular examples of
resident viruses are Meve, MrKlunky, Randex, and CMJ.
2. Multipartite Virus
This type of
virus can easily spread on your computer system. This is very contagious, takes
illegal actions in your operating system, in folders, and other programs on the
computer. They have the ability to infect executable files and boot sectors.
3. Direct Action Virus
Virus
actions directly attack certain types of files, usually files with extension .exe.
The main purpose of this computer virus is to replicate and infect files in
your folder, so that your files can become numerous, and can damage your files.
On lighter notes, they usually don't
delete files or affect PC performance and speed. It can be easily deleted by an
antivirus program.
4. Browser Hijacker
This type of
virus infects your web browser which will take you to various websites.
Usually, if you enter a domain name in the internet address bar, the browser
hijacker will open up some fake websites that can harm your computer. But don't
worry, currently most trusted browsers have already provided built-in features
that are able to block it
5. Overwrite Virus
From its own
name, this virus overwrites the content of the file, losing its original
content. It infects folders, files, and even programs. To delete this virus,
you must also get rid of your files. Therefore, it is important to back up your
data.
6. Web Scripting Virus
This virus
lives on links, advertisements, placement of images, videos, and layout of
certain websites. This can carry malicious code where when you click, the virus
will be automatically downloaded or will direct you to a malicious website that
contain viruses.
7. Boot Sector Virus
The boot
sector virus affects the floppy disk. They appear when the floppy disk is
important in booting the computer. Even though they are not very common today,
it still causes other computer units, especially those that are outdated. Some
examples include Polyboot.B and AntiEXE.
8. Macro Virus
Macro
viruses target applications and software that use macro programming code. This
virus can carry out a series of operations that affect the performance of a
program or software. Some examples of macro viruses are Relax, Melissa.A, O97M
/ Y2K, and Bablas.
9. Directory Virus
Directory
viruses change the file path. When you run programs and software infected with
a virus directory, the virus program also runs in the background. Furthermore,
it may be difficult for you to find genuine applications or software that have
been infected with a virus directory.
10. Polymorphic Virus
Polymorphic
viruses use special coding or encryption methods each time they infect a
system. With this, antivirus software is difficult to find and then uses
signature search. They are also able to replicate easily. Polymorphic viruses
include Bug Satan, Elkern, Tuareg, and Marburg.
11. File Infector Virus
This virus
also infects executable files or programs. When you run these programs,
activated file infector viruses can slow down the program and produce other
damaging effects. A large number of viruses are included in this category.
12. Encrypted Virus
This type of
computer virus uses encrypted malicious codes which make antivirus software
hard to detect them. They can be detected when they decrypt themselves during
replication. Although they don't delete files or folders, they can affect PC
performance badly.
13. Companion Virus
This is a
type of virus that does not survive without an existing file or folder. To do
damage, a file or folder accompanied by a companion virus must be opened or
executed. Some examples of companion viruses include Asimov.1539, Terrax.1069, and
Stator.
14. Network Virus
Basically,
this type of virus spreads through the Local Network Area (LAN) and via the
internet. This virus replicates through shared resources, including drives and
folders. When network viruses enter the computer, they search for their
potential prey. Malicious network viruses include Nimda and SQLSlammer.
15. Nonresident Virus
Non-resident
viruses is one type of computer viruses that replicate through modules. When
the module in this virus is executed, it will find one or more files as targets
to be executed.
16. Stealth Virus
Stealth
viruses do some trick on antivirus software by looking like they are real files
or programs and by intercepting requests to the OS. Some antivirus software
cannot detect them. Sometimes, it temporarily deletes itself from the system
without deletion.
17. Sparse Infector
Sparse Infectors
is one of the type of computer viruses that use different techniques to
minimize detection. They are "occasional" infecting viruses. For
example, they might only want to infect a program every ten executions. Because
of their occasional infectors, antivirus software is difficult to detect them.
18. Spacefiller Virus
Also known
as a "cavity" virus, spacefiller attaches itself to files and can
change the start of the program or change the encrypted code. They also apply
stealth techniques so that users cannot determine the increase in the file
code. The most popular Spacefiller is the Lehigh virus.
19. FAT Virus
Basically,
this type of computer virus damages the file allocation system where
information about files, including locations, exists.
20. ILOVEYOU Virus
The ILOVEYOU
virus is one kind of computer virus or worm. This virus spread via email with a
subject line that said "I love you", and it attack firstly in 2000.
And ILOVEYOU virus is one of the most famous and worst computer viruses of all
time.
21. Computer Worm
What is a
computer worm? Computer worms are one types of malware that spread copies of
themselves from one computer to another computer. Worms can replicate
themselves without human interaction, and they don't need to attach themselves to
a software program to cause damage.
22. Other Virus
Other
threats are not technically referred to as "viruses", but they also
have the same damaging effects as viruses. This includes adware, malware,
Trojans, and ransomware.
To prevent
this virus from affecting your computer, you should install at least 1 of the
best and most competitive antivirus software that can detect, block, and
eliminate all types of viruses from your device.
Examples of Computer Virus
Computer
viruses generally use some cheat on hosts or other types of computers to
reproduce copies of invading organisms. They spread from computer to computer
through electronic bulletin boards, telecommunications systems and shared
diskettes. Viruses are created by human programmers, for pleasure or envy, but
once they begin to spread they take their own lives, creating disturbances,
anxieties and paranoia behind them.
If a virus
is found on one PC, the PC must be isolated immediately. Viruses can be removed
by giving antidotes by studying viruses. The machine must be used only after
the virus has been removed.
Viruses
Viruses are
defined as programs that are included in other programs. It is activated by the
host program. It replicates itself and spreads to other people via floppy
transfers. Viruses infect data or programs every time a user runs an infected
program and the virus takes advantage and replicates itself.
There are two types of 'parasitic' computer viruses and 'boot' viruses.
Parasitic
viruses stick to other programs and are activated when the host program is run.
Trying to connect to more programs so that the opportunity to be activated
more. This spreads to other computers when the affected program is copied.
'Jerusalem' and 'Datacrime' are examples of parasitic viruses.
Boot Virus or
boot sector virus is computer virus that is designed to enter the floppy disk
boot sector. It works by replacing the first sector on the disk with a part of
itself. It hides the rest of itself elsewhere on the disk, with the first
sector copy. This boot sector virus is loaded by a built-in computer start-up
program when the engine is turned on. The virus loads, installs itself, hides
the rest and then loads the original program. On hard disks, viruses can occupy
the DOS boot sector or the master boot sector.
Reported Viruses
C-Brain:
Amjad and Basit, two Pakistani brothers, developed this software in January
1986 to prevent people from buying illegal software at low prices. This is the
most famous virus ever discovered and has a record of damaging several million
personal computers. This is designed to remain in the boot disk sector or close
to zero sector. The virus enters machine memory after the PC is booted with an
infected diskette.
Macmag: This
virus only attacks Apple Macintosh computers. Not much damage was reported due
to this virus. This was not noticed on compatible IBM PCs. It displays a
message of peace on the monitor and suicide.
Cascade:
This virus attacks IBM PCs and is compatible. The letters on the screen can be
seen vertically down to the bottom of the screen after the virus picks them up
in alphabetical order. This is a kind of parasitic virus. It attaches to other
programs and is activated when the host program is run. It will be copied to
another PC when the program is copied.
Jerusalem: This
virus was found in 1987 at Hebrew University, Jerusalem. And this virus was
designed to be active only on Friday, January 13 and deleted all files executed
on that day. This virus infects COM and EXE files. This is similar to the
Cascade virus because it is parasitic. This virus attaches to COM and EXE files
to damage the data.
Daracrime /
Columbus or October 13 virus: This virus is similar to Jerusalem and was
programmed to attack on October 13, 1989. Tracking zero computer hard disks is
destroyed and the contents of the disk cannot be read.
This virus are able to enters
COM and EXE files and damages your hard disk. The antidote called 'Vchecker'
was developed by the American Computer Society. Fortunately the virus was
discovered in March 1989 and the damage reported after October 13 was very small.
Bombs: These
are also known as 'Logic Bombs' and 'Time Bombs'. An event that triggers a
routine in a program that causes a crash program is defined as a 'bomb'. In
general, a 'bomb' is software that is included in a program by someone who
works in a company.
Conclusion
That was the
explanation of definitions, types, and examples of computer viruses. However, the virus mentioned above does not
only attack the computer, but your device such as smartphone can also be
attacked by these viruses.
So from now
on you should start checking your device now, whether your device is
infiltrated by a virus or not. Because like what you have read before, the
effects of computer viruses are very dangerous.
So pay
attention to whether your device seems to have strange symptoms like it feels
very slow or the application that is run often crashes suddenly, because that
could be one sign that your device is infected with a computer virus. And it
would be better if you read the full explanation of the symptoms of the virus, so you can protect your device
immediately.
And if you
realize that your device has a virus, then your device suddenly experiences a
lot of problems, you can try to read these tips from us to fix problems on your device.
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