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PC Security: Computer Viruses

Know Thy Enemy is rule number one when it comes to computer security. You can't fight or prevent something effectively if you have no idea what you are guarding against. In the online world, there are many enemies.

Those computer users known as Crackers and Hackers are the enemy. Crackers typically break into a system for the purpose of doing damage. Hackers, on the other hand, often break into systems just to see what is there, without any intention of doing harm. In fact, most large corporations, such as financial institutions, hire hackers on a full time basis. The hackers job is to try to break into the computer system. This is how the security holes are found and fixed. So, in this sense, most hackers are actually not the enemy, however there are people out there that call themselves hackers, who are actually crackers.

These people do more than break into systems, however. They also write malicious programs known as malware, such as viruses, worms, and trojan horses. A virus is a program that is typically hidden within another program. These are commonly delivered via email, in the form of attachments. The virus, once it has installed itself, looks for a host program. When the program runs, the virus runs. Once it runs, it is usually able to do what it was meant to do, and to infect other programs. It will even send itself to everyone in your address book.

Viruses operate in various stages. The first stage is the delivery, followed by the installation, infection, and finally the destruction phase. A virus may lay quietly on your hard drive awaiting a certain event, such as a certain date to trigger it. It will then deliver it's 'payload' which may mean file or program corruption, file deletion, messages, or even destruction of the operating system, leaving your computer unusable.

When computer viruses first made their appearance in our online world, they were commonly distributed via floppy disks. Today, however, they are delivered in downloadable executable files and email.

Worms are much like viruses. They can reproduce themselves, but they can also infect other systems on a network without a human doing anything further. Worms do not need host programs, and they do not need executable files to hide in, although they can also be delivered via email.

While viruses commonly infect individual systems, worms infect entire networks of computers. They commonly overload and overwhelm the resources for the network, which in turn causes data transmission slow down. Worms commonly insinuate themselves onto systems using a backdoor program. A backdoor is common for most networks, and it bypasses the login. Most programmers often leave a backdoor in a program so that they can easily get into the system or program if they need to for legitimate reasons.

A trojan horse is a program that the user thinks does one thing, but actually does another. When you think of a trojan horse, think of the Greeks. Remember that they built a large wooden horse to hide in, and the Trojans believed that the Greeks were giving them a gift, and took it into their compound walls. Once inside, the Greeks attacked the Trojans.

Trojans do not reproduce themselves. The software that they hide in may be quite useful in fact, but the trojan may erase files or data, corrupt programs, log keystrokes, and of course will usually install a backdoor program for other trojans to easily enter through. Trojans are commonly used to steal personal (read financial) information.

Virus software is the first line of defense against all of these threats, but it usually is not enough. For example, many virus detection programs won't detect worms, some won't detect trojan horses, and most won't detect spyware or adware. You should make sure that your virus definition is always up-to-date, install an anti-spyware program, spam blockers, and of course special software that detects trojan programs and worms as well, if your anti-virus program does not.

  PC Security: Index
  PC Security: Internet Browsers
  PC Security: Spam
  PC Security: Stopping Spam Part 1
  PC Security: Stopping Spam Part 2
  PC Security: Spam Scams
  PC Security: Email Security and Spam
  PC Security: Email Security
  PC Security: Computer Viruses
  PC Security: Protecting Computers From Viruses
  PC Security: Worm Viruses
  PC Security: Trojan Horse Viruses
  PC Security: Rootkits
  PC Security: Removing a Virus
  PC Security: Virus Hoaxes
  PC Security: Server Viruses
  PC Security: Home Network
  PC Security: Cell Phone Viruses
  PC Security: Spyware
  PC Security: Firewalls Part 1
  PC Security: Firewalls Part 2
  PC Security: Parental Control Software
  PC Security: Malware - Spyware and Adware
  PC Security: Data Backups
  PC Security: Pop Up Windows
  PC Security: Safe Public Computer Use

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