Types Of Computer Viruses
What Is A Computer Virus
There are all types of computer viruses but what is a computer virus? A computer virus has been defined as a set of computer instructions that reproduces itself and it may attach to other executable code. Usually this code is a short program that may either embed in other code or stand on it's own. In essence, this computer program is designed to infect some aspect of the host computer and then copy itself as much and as often as it has the chance.
It was estimated that a virus by the name of mydoom infected well over a quarter a million computers in one day back in 2004. There are tens of thousands of worms and viruses now being spread via the internet with new ones being discovered each and every day. It is often through quite innocuous and normal internet activities like the exchange of files like music, photos and others that many people are infected with these unwanted and sometimes dangerous programs.
The nomenclature that is now used to describe viruses has changed considerably over the last few years as more, if not most, computers are now on the internet. This has ushered in a change in the types of computer viruses toward a worm/virus hybrid and has caused the distinction between them to vanish.
There are a whole group of people that spend a tremendous amount of time looking for what have been termed backdoors into your computer so they can find ways to inject their code into your computer and use it for their own intentions.
What Does A Virus Do
The task of a virus is not always destructive like deleting files that may be important or something like causing your hard drive to crash. Many viruses these days are more interested in harvesting information from your computer and or using it as a zombie for their intentions like spam or other illegal purposes.
In times past it was often the intention of a virus to do damage just for the sake of destruction and maybe bragging rights among peers but almost all viruses today that are widespread have at their root some economic agenda.
How Does A Virus Spread
One of the intents of all types of computer viruses that gets installed on your computer will be to spread itself. This happens in a fashion that is not all that different from what happens with a virus in the human population. It is through exposure that the virus spreads when the computers defenses are down or non existent. Also like their biological counterpart the computer virus can be spread rapidly and are not very easy to get rid of.
Because the way a virus operates is to be stealthy, coupled with the rapid communications that happen between today’s computers, it is easy to dramatically increase the speed at which a virus that is targeting a newly discovered vulnerability can move around the web and around the world.
A virus that targets a network of computers can even more easily spread since so many computers are connected and most likely will have the same vulnerability and easy access to one another. Often viruses will spread via shared folders, email or over other media that is often exposed to other computers via removable media like cds and flash drives.
Because there are so many types of computer viruses, a virus can infect another computer unintentionally anytime that program is run and the virus is activated. Something like opening a email attachment or downloading a file off the internet or giving or receiving a copy of a program or file from a co-workers thumb drive can expose you and others to a computer virus.
Literally the gamut of these types of computer viruses can expose you whenever you have a downloaded file or a external drive attached to your pc. The most common way they spread is via email attachments or with the use or transfer of files via instant messaging.
The Types Of Computer Viruses
There are six broad categories or types of computer viruses:
1. Boot Sector Virus
2. File Infection Virus
3. Multipartite Virus
4. Network Virus
5. E-mail Virus
6. Macro Virus
Boot Sector Viruses
Viruses that aim at the boot sector of a hard drive are infecting a very crucial component of the boot process. The boot sector holds critical information that controls the hard drive and also the part of the operating program that is in charge of the whole boot process. These types of computer viruses go a long way toward the assurance they will be successful in their mission by absolutely loading into the system memory while the boot cycle is starting.
Unlike other viruses the boot virus does not affect files, instead it goes after the drive itself on which the virus is saved and this is part of the reason that it is no longer as big a threat as it used to be. Since the advent of cds and dvds and the drives that carry them it is not possible to infect the programs that they carry. In the days of floppy drives the virus could spread quite quickly from computer to computer via the disks but since it is not possible to infect a cd or dvd this virus has become almost a non threat. Another reason this types of computer viruses have become less common is that now operating systems stand guard over the boot sector and that makes it very hard for the virus to have any effect.
File viruses are coded so that they will attach themselves to exe files, compressed files like zip files and driver files. The can be set into actions when the program they are attached to is started. Then after the virus is set into motion it will attach itself to other programs and system files and start along it's intended path for which it was written. So you see it is a two prong approach. First depending on the types of computer viruses it will duplicate and then go about its intended mission. The virus will search through the programs in the system and find places to infect with the code and then it will activate when that program is run next time. It will continue to duplicate until it is all over the computer and probably any computer that is attached to the original system.
Often these viruses will harbor special code that causes them to be activated when certain events take place. The event often is a date or some other trigger event that is easily defined on any computer system you may have.
That which has been termed the multipartite virus are the types of computer viruses that are both a file virus and a boot sector virus. They enter the computer via various sorts of media and then embed themselves in the system memory. They then go into the hard drive and infect the boot sector. Once installed in the boot sector these types of computer viruses infect executable files and spread themselves in the system.
This is another virus that has past its prime for various reasons but in times past these types of computer viruses were responsible for many infections because they combined characteristics of two different viruses into one.
A virus that is especially made for networks is uniquely created to quickly spread throughout the local area network and generally across the internet as well. Most of the time is moves within shared resources like drives and folders. Once it finds entry into a system it will search for vulnerable computers in the network and likewise infect that system and do the same again and again always on the hunt for new vulnerable systems.
Most of the time a e-mail virus is one of those types of computer viruses that is generally a macro virus and it will multiply itself by seeking out the other contacts in a e-mail address book and then send itself to those addresses in hopes that they will activate the virus too. Thus it spreads over and over again exponentially. There are even times an email virus can spread by only previewing it in the mail client. One that was very successful in spreading worldwide was the ILOVEYOU virus and it was destructive too.
Macro viruses as the name implies, will infect files of programs that use macros in the program itself. The most common of these are the Microsoft Office files created in Excel spreadsheets, Word documents, Access databases, Powerpoint presentations and these type of files from AmiPro and Corel Draw and others.
These types of computer viruses are programmed using the language that the application understands and not in the language of the operating system thus they are operating in a way that is independent of the operating system so it can infect any kind of system be it Mac, PC or even Linux just as long as the computer is running the application that understands the macro virus. As the macro language has become more and more powerful the threat of these types of computer viruses has graduated to more critical types of computer viruses. These viruses have been around since 1995 and the first was found to infect Microsoft Word but now have moved to other programs and they number in the thousands.
One should always be on the lookout for these types of computer viruses and should take every precaution to avoid them. Be ever watchful of every file you open or else you may be looking for my next hub on how to remove these types of computer viruses.
The Difference Between A Virus & A Trojan
If We Only Knew Then What We Know Now
Help Me Pick My Next Hub Topic
I would very much like your help picking my next related topic about computers and would like you to look over this list of questions I came up with and either vote for the one that you think is most interesting or make a comment in the comment section. Thank you in advance for your help. Here is the list:
how to protect your computer from a virus worm
how to create a computer virus that opens and closes a cd drive
what is a virus + computer security
what computer virus removes email icon?
how can i portect my computer from a virus
how to clean a virus from computer
who was responsibe for unleashing the melissa computer virus
how to make a virus that erases everthing on your computer
how to fix my computer when its infected by a virus
how to inflict an email computer virus collection
get rid of virus when computer won't boot
how do i know if my computer has the conflicker virus
how is the computer virus time bomb transmitted
how can someone get caught creating a computer virus
how does the computer virus stealth get on your computer
how to delete virus in the computer
how to get rid of computer virus free
what are some common warning sings for a computer virus
Vote For My Next Hub Topic
Tanuja bhatt on August 05, 2020:
It is very inserted very good
Tanuja bhatt on August 04, 2020:
It is very inserted.
Toni on April 09, 2015:
Yes studys r tooo boring n learing about virus is too boring
Youni on January 18, 2015:
I got sophos for my mac beascue I don't want to be spreading around PC viruses by accident. I have found a few times that an Email I have gotten has had a virus in it and I wouldn't have known about it. I guess you can say that I stopped my friend's computers from getting the virus. I also think it's a good idea to have the software there just in case. I'd rather put a lock on my door and put a good security system in place so that the bad guys won't get in once they start trying to do so.
Akshit Solanki on December 12, 2014:
This is very good but not excellent.
Garima on December 12, 2014:
Chimpanzee are always shouting like Salah
yeshvi on December 11, 2014:
Monika pandey on December 11, 2014:
but it is so boring without pics and video
Yojesh Baur on December 11, 2014:
priyanshi on December 11, 2014:
Thank You !!!!!!!!!!!!!!!!!
Sahillllllll on December 11, 2014:
Ve annu chutye saaale harami
Yojesh Bauri on December 11, 2014:
Annu on December 11, 2014:
Your website is bad . Because there is no advantage of virus. Bad............................
Khush Patel on December 11, 2014:
your website is very nice
anil kumar on February 20, 2014:
which is the name of virus thal its create all data shortcut
mona on January 03, 2014:
I have learnt about virus
Yojesh Bauri on September 30, 2013:
aap to hit ho gaye
aapaka jabab nahi
Patricia L. Loranger on September 09, 2013:
I went into a site & took 2 pictures & placed them into my pictures. These 2 pictures have multiplied their selves by hundreds of times & I can't get rid of them.
Priyanka on April 10, 2013:
Thank you so muses...........ch CAVERSON.............. i really glad to hear you and know much more about viru
siti on April 03, 2013:
its very clean and important knowledge i get 10q very mach
PANKHURI on May 26, 2012:
YOUR WEBSITE IS VERRY VERRY SLOW.
priya on May 22, 2012:
i have learnt much about viruses ............
sharm1205 on March 31, 2012:
yeah ... ihv learnt bout virus..
sharm1205 on March 31, 2012:
yeah ... ihv learnt bout virus..
Jaja on March 27, 2012:
Can one ever be confident of preventing virus through anti virus
merry mayurakhee on February 09, 2012:
it is very good and i have learnt many things about computer viruses.
KENTH on January 26, 2012:
THANK A lot
Ajak Ateng on October 20, 2011:
Good to hear that from you Caverson!!!I usually craned my neck for some one to help me,but now I got to learn from you and I am really wondering who creates Virus and Why did he/she do So.
tomiwa raji on October 12, 2011:
Erline on September 22, 2011:
cell phone jammer here
PAMark from Victoria, BC Canada & Boquete, Panama on April 12, 2010:
Good stuff Cav! I hate viruses and would love to get my hands around the neck of just one of those creeps that creates them!
Caverson (author) from Left Coast on March 17, 2010:
Precious, that is a very hard question to answer as there are so many different types and kinds of things that will infect your computer. Even the definition of the word 'virus' can be open to debate in the computer world. I own a computer repair business and by far virus removal is the thing that I most often deal with as the primary cause for the call to my office for a repair. If you would like ask a more specific question and I will try to help you out. In the mean time look at the video I posted above "The Difference Between A Virus & A Trojan" and get an idea of the answer to your question.
precious on November 23, 2009:
what is the most critical type of virus and how can i prevent it?