Viruses and some types.

Viruses:

• It is a program or a piece of code loaded onto your computer without your knowledge and run against your consent.
• A virus is attached to any file or program itself and spreads from one computer to another, leaving infection as travel.
• All viruses are attached with a (.exe) type file, which means the virus may be on your computer or device but, that can run only when you or anyone run that.

Worms:

• A worm is similar to the virus and it is also a sub-class of the virus.
• A computer worm is a virus that spreads by creating duplication into the Drive.
• Computer worms can send copies of worms to another network, computer, or drive easily so that is more active than the virus.
• The worm can send its copies to another computer through the network, Bluetooth, mail, or infected web pages.

Hints that you can think there is a worm in your PC :

• There will be showing the new unknown icon on the desktop or any else other path.
• Your computer becomes slower than before.

Intruders:

An intruder is someone that enters the place without any kind of permission or invitation. Also, it knows as hackers or crackers.

• Three classes of intruders:
• Masquerader
• Misfeasor
• Clandestine user

A. Masquerader:

• They pretend to be someone that he was not.
• An individual who is not authorized to use the computer and who penetrates a system's access controls to exploit a legal user's account.

  B. Misfeasor:

• The authorized person doing unauthorized actions.
• that was a permitted user.
• A legal user did not have permission to access data or have access but not for that work, he/she misused his/her privileges.

  C. Clandestine User:

• A clandestine user is an individual who seizes supervisory control to avoid the system's security mechanisms such as manager or access controls.

Example of Intruders:

• Gussing and Cracking passwords
• Copying a database containing credit card numbers.
• logged in to the workstation without permission.