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What is a computer virus and how do I get one?
Viruses are simple but often surrounded by much hype and misinformation. (Many people want you to believe you must be an expert to understand viruses, but this just isn't so!)
A computer virus is a program that makes copies of itself and infects diskettes or files. Computer viruses can spread to other computers and files whenever infected diskettes or files are exchanged. Often infected files come as email attachments, even from people you know. The email senders have no idea that they are passing on a file with a virus in it.
Some computer viruses can erase or change the information stored on your computer, other viruses may do little or no harm to your system. Writing and releasing any virus is prohibited by university policy, and anyone who does so will be held legally accountable for damages.
These infected programs can be files containing executable code (most commonly .COM and .EXE files), or boot sectors. A virus can only infect your PC if you execute an infected program or by booting from a diskette containing an infected boot sector.
Types of computer viruses
There are currently four types of computer viruses, each spread in a different way.
These viruses are spread by sharing document files from MS-Word (version 6.0 and above) or MS-Excel (version 5.0 and above). Macro viruses are a frequent cause of virus infections, and they can infect both PCs and Macintosh computers. After your computer is infected with a macro virus, any Word or Excel document you create or open may also contain the virus.
- "Boot Sector"
These viruses are spread by sharing diskettes between different computers. Any diskette can spread a boot sector virus --even if it is not a bootable system diskette. If you share files by sharing diskettes, you can spread a boot sector virus to other computers, which then can infect other diskettes.
These viruses are spread by sharing program files. Because most users share programs less frequently than they share data or document files, this type of virus is less common than others. A program virus can infect other programs and damage data files on your computer.
- "Email" or "Hoax"
These viruses are not really virus programs at all. They are email messages sent by well-meaning people to warn others about a new virus they read of. These false warning messages usually say "be sure to send this to everyone you know" and warn of major damage to your computer or files. Hoax virus warnings can cause huge amounts of Internet traffic and unnecessary worry to others. Please check with someone knowledgeable about computer viruses before you forward such a message.
- A virus can not appear on your computer all by iself. You have to get it by sharing infected files or diskettes, or by downloading infected files from the Internet.
- A write-protected diskette can not become infected with a virus.
- You can not get a virus by reading the body of a Pine email message, although one could be carried in an attachment (e.g., a Word or Excel file). These attachments should be scanned before You read them.
How do I protect my computer?
There are several things that you should do to protect your computer from virus infections:
- Use a high-quality anti-virus program, and be sure to update it regularly. Use it to scan any files, - programs, software, or diskettes (even new software from a commercial company) before you use them on your computer.
- Make back-up copies of important documents or files and store them on separate diskettes. Making backups will also protect your information against accidental file deletion, diskette failure, and other damage.
- Whenever you use a computer in a campus lab, be sure to reboot or run "cleanup" before you start your session and log out when you end your session.
- Do not share commerical software with anyone. It is a violation of the author's copyright to distribute such material, and it is a way to spread viruses.
- When you get public domain (PD) software for which the author has granted permission to make copies, get it from a reliable source. (For example, and individual you do not know is not a reliable source.) Before you run PD material, use an anit-virus program to inspect for known viruses.
- Make sure that you have your e-mail program set-up so that it does not run attached files or programs.
- Never run an executable file you recieved without running an anti-virus utility.
- Always scan your diskettes and files after using them on another computer.
- Always scan all files you download from the Internet.
- Always scan Word or Excel file email attachments before you read them.
- Get Protected. If you don't have virus protection software on your computer we recommend you get a program as soon as possible.
How do I get anti-virus software?
You should install the latest versions of anti-virus software on your desktop computer to protect it from viruses.
Tulane University Technology Infrastructure Services download page has McAfee's VirusScan for Windows and Linux environments and Virex for Mac OS software. TIS Downloads
You also can download anti-virus software directly from the Web. Here is a list of several virus protection software sites:
What if my computer gets a virus?
Not all damage to your programs and files are caused by viruses: worn out floppies, failing hard drives, user error, and poorly written programs can all cause you to lose data. If your computer is behaving strangely, or if you think your computer has a virus, use an anti-virus program to find out.
If your computer is infected with a virus, DON'T PANIC! Use an anti-virus program to remove the virus yourself, or turn your computer off and find someone who knows how to remove the virus.
If a virus is active in memory, it may prevent anti-virus programs from working correctly. To be sure no virus is active, turn off your computer and reboot from a known-clean system diskette before you begin the disinfection process.
Eliminate all copies of the virus as quickly as possible. Check all your diskettes, and warn anyone else who may have infected files or disks.
Remember, most viruses can be removed without permanent damage to your system, and most virus infections can be prevented. With proper care, your computer can remain virus-free.
Anti-virus software should be installed when the personal computer is initially configured. The software should be updated weekly with new virus definitions, and your vendor may provide an automated update feature. Organizations may benefit from using several brands of anti-virus software.