First of all what is malicious code?
Malicious code or malicious software is a software program designed to access a computer without the owners consent or permission. Meaning it is meant to trick the operator into allowing it access to their computer and programs by means of deceit, deception, and or disguise. Most often through an email, music, or some other program.
Malicious code is most often referred to as a virus, this term is however used loosely as there are many different forms of malicious code such as viruses, malware, spyware, adware, rootkits, trojans and worms.
For the most part there is a very thin line between these classifications or what category type malicious code falls under. This is mainly based on what the software was designed to do or its functionality.
For example if you receive a pop-up on your computer trying to sell you something, this would most likely be classified as adware or advertizing software.
Adware is often use in conjuction with spyware. Spyware is a piece of code or software designed to view, monitor, and record what the user is doing online, basically spy on you.
Example of how they are used together. Lets say you are online looking to buy a computer. Like most people you shop around looking for the best bang for your buck. You visit a variety of websites and unknowingly pickup a piece of malicious code. The next thing you know, out of no where you start getting pop-ups trying to sell you computers, computer equipment, accessories and sometimes even anti-virus software. Most likely you have just experienced adware and spyware working together.
What basically happened was the spyware saw what you were doing online i.e. looking to buy a computer. It then relayed this information to an adware server, the adware then started producing advertizement windows or pop-ups related to what you where doing.
Now that we have a basic understanding of viruses and malicious code we can get on with the origins of this software.
What was the first virus?
There where actuality three viruses that where the first. There was the original virus, the original virus for apple computers, and the original virus for PC computers.
The first know and accepted virus created the original was the creeper virus or worm. Created in 1971 by Bob Thomas at BBN. The worm was designed to self replicate or copy its self to remote computers and display "I'm the creeper, catch me if you can!" this virus was created and controlled in a lab environment. although experimental and not damaging to the computer it infected this virus still had the intention to be a nuisance and that makes it technically the first virus.
The first virus created outside a controlled environment was for the apple none the less, this virus was called Elk Cloner. A virus designed to display a poem on the screen of the computer user. It was create by a gentleman by the name of Richard Skrenta in 1981.
The first virus created for the PC computer out side a controlled environment was developed five years later in 1986. This virus was named brain by its creators the Farooq Alvi Brothers of pakistan. Brain was a boot sector virus designed to deny access to files stored on a floppy disk.
By now you are probably asking well, what was the first anti-virus? And I answer the first anti-virus was a program called reaper or reeper not sure on the exact spelling. Reaper was designed to get rid of the creeper virus. This program was produced by the creator of the creeper virus Bob Thomas.
How We Got to the present day viruses?
This is quite simple. In the beginning there were limited forms of transportation means for viruses and malicious code to replicate themselves through such as floppy disks. And in the early days of the internet there were very minimal connections. Being the fact that the only people with a connection was the military and educational facilities.
After the first home based computers were developed, the internet size increased as well as the number of connections. When this increased so did the means of virus replication. As the personal computer became more prominent so did the programs, media and the communication forms. From email, bulletin boards, instant messaging, p2p networks, and flash drives just to name a few.
Lets face it as we grow and expand so did viruses and other forms of malicious code.
The present day virus
The present day viruses come in many forms such as stealth, variable key encryption, polymorphic, metamorphic and self modifying. Basically this means the viruses hide, encapsulate, recapitulate and rewrite themselves to avoid detection form anti-virus software. This makes it harder to catch, slowdown or even stop certain viruses for spreading at a rapid speed to unsuspecting host computers.
Some of theses viruses are even designed to attack and disable anti-virus software. Delete your update definitions so it looks like your anti-virus software is working and it is, just not properly, to put it plainly it doesn't know what its looking for.
If you would like to know more information about these types of viruses. I will be writing about them in future articles under stealth, variable key encryption, polymorphic, metamorphic, and self modifying viruses.