University of Wisconsin Knowledgebase
This document details how to increase your protection against computer viruses.
Viruses are an almost inescapable part of the Internet experience. When it comes to dealing with the hazards posed by viruses, prevention is much easier than a cure. The following tips will prevent most viruses from ever affecting your computer. For more background information on viruses refer to Virus Information.
The computer viruses that have historically caused the most damage (such as Melissa and LoveLetter) are those that spread via e-mail. A basic plain text e-mail message is unable to transmit a virus. It is attachments to e-mail messages that potentially contain the hazard. Unexpected attachments or those from unknown senders should be deleted. Attachments sent from known and trusted sources may also contain viruses -- it's a good practice to contact the sender to confirm that the attachment is legitimate before opening.
If you are unsure about what an attachment is or what it does, leave it alone. If you have determined that an attachment is a virus, delete the email and the attachment.
Microsoft Word documents (.doc files) and Excel spreadsheets (.xls files) can potentially contain a type of virus known as a macro virus. Do not open these types of attachments unless you have enabled macro protection in Word and Excel. For detailed instructions on how to enable macro protection see Word-Enable Macro Protection and/or Excel-Enable Macro Protection. With macro protection enabled, Word or Excel will give you the option to enable/disable a macro for each document/spreadsheet you open. In general, you should open documents with macros disabled unless you know specifically what the macro does.
Common extensions for executable files are:
The only file types that are definitely safe are those that end with:
If the subject line or the body of an e-mail states that the attachment is a certain type of file or if the file icon implies a certain type of file and the file extension does not match, delete the file. Also delete the file if it has multiple extensions such as picture.gif.exe. This is not really a picture file but an executable program that could potentially be a virus. If you trust the sender, contact that person to determine what you were supposed to have received.
Every time you put your floppy disk into the disk drive of a computer, you risk picking up a virus on the disk (the labs on campus have the latest antivirus software installed on their computers, so your risk of picking up a virus from them is smaller). Good antivirus programs (like McAfee and Norton) are designed to automatically intercept and scan any files coming into your computer (whether via floppy disk, Zip disk, or web download), so make sure that your anti-virus software is installed and running on your computer before you use your floppy disk in it.
Any time that you share a directory or a hard drive so that others on your local network can access them, you are opening yourself up to the risk of infection or malicious tampering. For this reason, we recommend that you do not share any of your files or folders over the network without the approval of your local network administrator. If you do choose to share your resources over the network, here are some precautions to take.
Do not share your entire hard drive. Do not share your root (C:\) directory or any of your Windows directories.
Set the access permissions to your shared folders to "Read." With "Read" access, others can still copy and see files in your shared directory but they cannot make changes to your files or delete them and if they can't, then neither can a virus.
Protecting your shared directories with passwords will limit access to only those individuals with whom you have entrusted the password.
Antivirus programs can be configured to regularly check your computer or even your incoming
e-mail attachments for viruses. Because viruses are being constantly created or changed, it is
important to use a program that provides regular updates. University Affiliates can obtain
Symantec Antivirus free of charge by visiting DoIT's Security Site .
Apple users should note that there are currently no wild viruses for MacOS 10, and thus at
present Antivirus clients for MacOS 10 are unnecessary burdens.
New or modified viruses are regularly unleashed on the Internet. Updating your antivirus software so that it contains the latest virus definitions will decrease the likelihood that you are affected by a new type of virus. Here are links to the virus updates for the most popular anti-virus programs.
More information and help on updating your antivirus software can be found here. Symantec Antivirus - Running Live Update
Microsoft and Apple both regularly release security updates that fix security holes in the Windows and in the Macintosh operating systems. These holes make you system more susceptible to viruses and allow them to be spread more easily. To get the patches follow these instructions.
In a worst case scenario, a virus may corrupt or destroy data on one or more files. Regular backups will allow you to recover more easily in the event that a virus damages your files.
If you are sharing data that resides on disks or other portable storage media, use the write-protect tab to prevent accidental viral infection.
| Keywords: | virus prevention protection virus anti savce nav4mac norton symantec antivirus protecting computer | Doc ID: | 613 |
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| Owner: | Jeff W. | Group: | Help Desk |
| Created: | 2000-10-11 | Updated: | 2008-03-25 |