Virus

• Spreads from one computer to another by attaching to a program or file.
   
• Can not infect your computer unless you run or open the infected program or file.
   
• Replicates itself.
   
• Can replicate by e-mailing itself to people in your e-mail address book.
   
• Can not be spread without some human action like running the infected program.
   
• Uses computer resources, such as memory, which could shut system down.
   
• Could damage software, hardware, or important files.

Worm

• Is a type of virus.
   
• Can not attach to another program or file.
   
• Replicates by creating copies of itself.
   
• Spreads from one computer to another usually through computer networks.
   
• Looks for security holes in the Operating System..
   
• Can be spread without human action.
   
• Uses computer resources, such as memory, which could shut system down.
   
• Can damage hardware, software, or files.

Trojan Horse

• Appears to be useful software but will do damage once installed or ran.
   
• Does not replicate.
   
• Gives malicious users access to your system.
   
• Uses computer resources, such as memory, which could shut system down.
   
• Can delete files and destroy information on your system.
   
• Can erase your hard drive.

Signs of Infection

• The performance of your computer system slows down.
   
• The look of your browser or PC has changed; i.e. new icons appear on your desktop.
   
• New toolbars have been added to your browser software. Toolbars can contain spyware or adware attached.

Solutions

• Keep your operating system up-to-date.
   
• Install anti-virus software on your system and download updates frequently.
   
• Install a Firewall which prevents unauthorized use and access to your computer,
  Or Turn on the Firewall if you have Windows XP.
  (Click on Start; Go to the Control Panel; Click on Window Firewall icon)
   
• Back-up system.
   
• Never open, accept, or download a file in Email or Instant Messaging from someone you don't know.
   
• Avoid programs from unknown sources.

Links

CERT: "A center of Internet security expertise."

Home PC Firewall Guide

How Stuff Works: How Computer Viruses Work

Mcafee: Virus Information

Microsoft Security and Security at Home: Protect Your PC

MSNBC: "Sasser worm author confesses in court"

Symantec: Threat Explorer: Provides information on the latest threats.

Take a Bite Out of Cyber Crime

Trend Micro: Housecall: Scan your PC for viruses and spyware free.

United States Computer Emergency Readiness Team

United States Department of Justice: "Creator of Melissa Computer Virus Sentenced to 20 Months in Federal Prison"

Webopedia: An online encyclopedia of computer technology

The Difference Between a Virus, Worm and Trojan Horse

Wired News: "Code Red: Is This the Apocalypse?"