What is a virus?

What is a virus? A virus can be spread through internet and network connections or on physical media such as floppy drives, USB drives, or CD-ROMs. Many programs people say is a virus is actually a form of malware, spyware, ad-ware, worm, or Trojan horse. A virus is able to reproduce itself from one device to another.

 The first virus was named the “Creeper” virus. It was first detected on ARPANET which later became the internet. Bob Thomas at BBN Technologies wrote it in 1971 as an experiment. It would display the message “I’m the creeper, catch me if you can!” on the remote machines. A program named “Reaper” was created to delete the “Creeper” virus.

 Viruses come in many forms:

1. A boot sector virus will copy itself to the first section of your hard drive and will be activated when you boot-up the machine. We will discuss later how to clean these up.
2. A macro virus will use another program such as Word, Excel, or Access to spread to other documents.
3. Root-kit virus is an undetectable virus. Root is the administrator user account on Linux machines. Rootkits are usually installed by Trojan horse viruses and will hide themselves in with operating system files.
4. Memory resident virus will sit in the RAM (Random Access Memory) after a program initiates the virus from the hard drive.
5. Polymorphic virus will create many copies of itself, but, it will also change its digital signature each time which makes them difficult to detect.
6. Logic/Time bombs are viruses that activate on a certain day or on a certain event. In 1991 there was the Michelangelo virus.
7. Browser high jacking is when a program will take over a browser by redirecting to preset websites or corrupting search results.

 What is a Trojan horse? A Trojan horse can be very destructive. It will mask itself as a program that you want, but, ends up stealing information or damaging your system. Unlike a virus it does not replicate itself. The term comes from the Greek myth of the giant wooden horse in the Trojan War.

 What is malware? Malware or “malicious software” is a program that is made to gather information, make something unusable, or gain access to something that is restricted. Malware can be something that is just annoying to very dangerous.

 Malware is a blanket term which covers viruses, worms, Trojan horses, spyware, malicious adware, and root-kits.

What is spyware? Spyware will collect information about users without their consent. They can include a key logger which will record every key that is pressed on your keyboard which is later relayed to the malware maker.

What is a worm? Like a virus a worm is self-replicating. They will use a computer network to send copies of itself to other computers without any user intervention. The reason this is not a virus is due to the fact that it harms the network and does not modify individual files on the computer.