Computer Viruses Standard A-4 (Safety Unit)

Introduction As computer users, we are all familiar with the term computer virus But, do we really understand how these nuisances work?

Background Computer viruses became widespread in the 1980’s due to many factors The increased usage of computers Trojan Horse Floppy disks These factors set the stage for a technological petri dish for computer viruses to flourish

Definition A virus is a program that reproduces itself, hides in other computer code without permission, and does nasty or undesirable things not intended by its victim. Computer viruses are called viruses because they share some of the traits of biological viruses. Computer viruses pass from computer to computer like a biological virus passes from person to person.

FACTS Computer viruses were named after their biological counterparts because of their similar traits A virus passes from one entity to another A virus can cause inconvenience and suffering A virus can spread into an epidemic

Types of Viruses Virus—small piece of software that piggybacks on real programs E-mail viruses—an e-mail virus moves around in e-mail messages and usually replicates itself by automatically mailing itself to dozes of people in the victim’s e-mail address book Worm—a small piece of software that uses computer networks and security holes to replicate itself Trojan horse—a computer program that claims to do one thing (it may claim to be a game) but instead does damage when you run it (it may erase your hard drive)

Initialization When first turned on, a computer loads an operating system or DOS into main memory from a disk When an infected file is run, that file is loaded into main memory also Once the file begins to execute, the virus becomes “active”

Reproduction Typically, its first objective is to replicate (or reproduce) “Virus programs, typically written in machine code, usually employ DOS commands to commandeer system resources that the virus must use.”

Macro Viruses Macro viruses are the most common virus today Unlike executable viruses, macro viruses cannot infect any file Microsoft Word documents & Excel spreadsheets The reason is the convenient macro languages that automatically perform tasks with little to no user input Once an infected file is opened, the virus copies itself into the global template used to store global macros

Evolution Luckily, executable and boot sector viruses are declining because of CD’s Computer technology is ever growing. Along with it, unfortunately, comes the evolution of computer viruses

The Computer Worm Also known as the email virus This new virus takes advantage of the World’s growing dependency on electronic mail The most famous is the Melissa virus of 1999 It was the fastest spreading epidemic in history

Code Red Worm FBI agent Dave Thomas mentioned Code Red in his speech What is Code Red? Search the following web address or create a search for Code Red to read information about the Code Red Worm http://abcnews.go.com/Technology/story?id=98374&page=1

No Laughing Matter U.S. Businesses lost $5 billion to $6 billion due to computer viruses Viruses have penetrated the computers of: NASA The Defense Data Network Capitol Hill The 2nd Circuit Court of Appeals IBM The White House A British Nuclear Power Plant The Naval Ocean Systems Command At least 2 viruses infiltrated Allied computers in 1991 during the Gulf War

Discussion Questions Why do you think someone would want to create a virus, knowing that it would harm others and their computers? How can we prevent ourselves from becoming a victim of a computer virus? Hard Drive: the internal storage unit for software in the computer Computer Software: the programs that a computer uses to complete a task E-Mail: (electronic mail) messages sent from one computer to another Floppy Disk: a temporary disk which is used for storage and retrieval in a computer Crash: this occurs when the hard drive software becomes scrambled or deleted and causes the computer to malfunction Download: the process of acquiring a file or program from another computer Internet: the network of phone lines, computers, and devices that connect computers worldwide Anti-Virus Software: software application programs which will scan disks or other programs being loaded into a computer, detect a virus, and stop its spread Cyberspace: the virtual world of digital communication

An Ounce of Prevention Don’t share floppy disks with anyone. Don’t download anything from the Internet Install anti-virus prevention software on your computer. Never recycle floppy disks that you know once contained a virus. Don’t download an attachment file from the Internet because it could be infected with a virus. Hard Drive: the internal storage unit for software in the computer Computer Software: the programs that a computer uses to complete a task E-Mail: (electronic mail) messages sent from one computer to another Floppy Disk: a temporary disk which is used for storage and retrieval in a computer Crash: this occurs when the hard drive software becomes scrambled or deleted and causes the computer to malfunction Download: the process of acquiring a file or program from another computer Internet: the network of phone lines, computers, and devices that connect computers worldwide Anti-Virus Software: software application programs which will scan disks or other programs being loaded into a computer, detect a virus, and stop its spread Cyberspace: the virtual world of digital communication

An Ounce of Prevention (continued) Never double-click on an attachment that contains an executable that arrives as an e-mail attachment. Attachments that come in as Word Files (.DOC), spreadsheets (.XLS), images (.GIF AND .JPG), etc., are data files and they can do no damage. A file with an extension like EXE, COM, or VBS is an executable file, and an executable file can do any sort of damage it is designed to do. Once you run it, you have given it permission to do what it was designed to do on your computer. Hard Drive: the internal storage unit for software in the computer Computer Software: the programs that a computer uses to complete a task E-Mail: (electronic mail) messages sent from one computer to another Floppy Disk: a temporary disk which is used for storage and retrieval in a computer Crash: this occurs when the hard drive software becomes scrambled or deleted and causes the computer to malfunction Download: the process of acquiring a file or program from another computer Internet: the network of phone lines, computers, and devices that connect computers worldwide Anti-Virus Software: software application programs which will scan disks or other programs being loaded into a computer, detect a virus, and stop its spread Cyberspace: the virtual world of digital communication

Antivirus Strategy

Debate/Discussion Suppose a person’s medical records were corrupted by a computer virus, and that person died because of faulty (or missing) medical information. If you were the judge and were to decide the fate of a guilty computer virus creator, what you you decide? How did you come to this conclusion? Hard Drive: the internal storage unit for software in the computer Computer Software: the programs that a computer uses to complete a task E-Mail: (electronic mail) messages sent from one computer to another Floppy Disk: a temporary disk which is used for storage and retrieval in a computer Crash: this occurs when the hard drive software becomes scrambled or deleted and causes the computer to malfunction Download: the process of acquiring a file or program from another computer Internet: the network of phone lines, computers, and devices that connect computers worldwide Anti-Virus Software: software application programs which will scan disks or other programs being loaded into a computer, detect a virus, and stop its spread Cyberspace: the virtual world of digital communication

Popular Anti-Virus Software Program Norton (Symantec Company) McAfee (Network Associates Company) Command Software Systems, Inc.

Sources http://www.howstuffworks.com/virus.htm http://www.cert.org/other_sources/viruses.html (numerous resources on computer viruses, hoaxes, antivirus software, etc.) www.animationfactory.com (virus template for PowerPoint)