Viruses and Worms

In general terms a virus is a program that runs on a system against the owner's or user's wishes and knowledge. Viruses have one or more methods they use to spread. Most commonly they will attach a file to an e-mail message and attempt to trick victims into running the attachment. Virus Damage In most cases, viruses can do any amount of damage the creator intends them to do. They can send your data to a third party and then delete your data from your computer. They can also ruin your system and render it unusable without a re-installation of the operating system. Most have not done this much damage in the past, but could easily do this in the future. Usually the virus will install files on your system then will change your system so the virus is run every time you start your system. It will then attempt to replicate itself by sending itself to other potential victims. The normal effect a virus will have on your system is that over time your system will run slower. Also when you are using the internet your connection may seem to run slower. Eventually you may have trouble running programs on your system, your system may freeze, and in the worst case you may not be able to get it to boot up when you turn your computer on. How Viruses or Worms Spread Most commonly viruses today use e-mail to spread however they have used one or more of the following methods to spread in the past. Some viruses will load themselves onto any part of a writable removable drive as possible and spread from computer to computer as people use the removable drive. A worm is a program similar to a virus that will exploit a vulnerability in an operating system or application that a computer user is running. The best defense against a worm is to have either a personal firewall on your system or be behind a corporate firewall. Another good defense is to update your system regularly. All you need to do to get a worm is to connect an unpatched computer to the internet or infected network when your computer does not have firewall protection. Most viruses will spread themselves using e-mail attachments. They may tell the user that they neet to open the attachment to get the rest of the information that is being sent to them. Many times the virus may claim it is an administrator and the user needs to either read the data or install a program on their system. Viruses have even claimed to be Microsoft sending a system patch as an attachment to the e-mail. Microsoft would never send a system patch through e-mail.  http://www.comptechdoc.org/basic/basictut/