Viruses propagated through e-mail attachments

Questions about viruses always are hot topics whenever computer users get together.

Viruses are small computer programs written usually by young, smart computer geeks. Some are malicious while others are harmless and just point up security leaks in particular programs or systems.

Almost all viruses are propagated via email messages that contain attachments. An attachment is something that comes along with an email message and can take many forms. Commonly, personal attachments are copies of pictures sent from family or friends. Attachments are "opened" or "executed" by double clicking on the attachment file. In most cases a picture is displayed and all is well. In some cases, however, clicking on an attachment may cause a virus program to be executed in your computer.

How does a computer user know when an attachment may contain a virus? Almost all attachments are shown with a "filename" followed by a dot (period) and three additional letters known as "extensions." Picture files may look like "kids.jpg" where the ".jpg" is a common type of picture file. Some pictures come as ".gif", ".bmp", or other common picture extensions. Unfortunately, you must be aware of these "innocent" extensions. Picture files do not contain viruses. Either do text or ".txt" files.

However, there are certain extensions that indicate files that MAY contain a virus. These typically are ".vbs" (visual basic), ".bat" (batch), ".exe" (executable), ".pif" (program information files) or ".scr" (screen saver) file extensions. Also there are a certain class of viruses that MAY be contained in common ".doc" (Microsoft Word) or ".xls" (Microsoft Excel) document files.

There are two main ways to protect our computers from viruses. First and foremost, each computer should have a virus protection program installed. There are two primary suppliers of these programs; Norton and McAfee. Both supply their programs on compact disks or downloadable from the Internet for around $60. Norton seems to be the most popular.

Once installed, these programs make use of "virus definition files" which contain the latest information about viruses. It is imperative that these files are UPDATED whenever new viruses appear. Either program will indicate when new definition files are available and they can be downloaded from the Internet. Usually these updates are free for a period of time and further updates can be obtained by low cost subscriptions. All the current programs protect against viruses obtained from diskettes or other sources as well as from email attachments

Personally, I take advantage of a subscription service called "Virus Scan On-Line" from McAfee. I pay a yearly subscription fee for which I obtain not only the latest updates but receive any UPGRADES to the program itself. This way I do not have to purchase new copies of the program when the ability to update expires. Information about both companies can be found on the Internet at (Norton) and (McAfee).

The second way to protect our computers, and possibly the easiest, is to NOT open attachments unless you know precisely who sent them and are assured they are virus free. I make a rule to not open anything but picture attachments even if I know the source because they may have been sent to me by someone who is forwarding them from someone else. Additionally, the young, smart geeks may have written a new virus for which the companies have not yet found a cure.

Viruses are complex animals and take many forms but it is rather easy to protect our computers from them using the above simple precautions. In another column we will discuss what to do if you get a virus.

If you would like to hear more about viruses, or other computer topics, visit "Coffee and Computers" at the Tustin Area Senior Center, 200 S. 'C' Street, any Friday morning starting at 9 a.m. Bring your questions or just come in and visit.

In the mean time, keep the neurons happy, synapses snapping and enjoy computing.


Dr. Art Holub is a long time resident of Tustin and teaches computer and Internet courses at the Tustin Area Senior Center and the Tustin Adult School. Visit his web site at: This column is written to address the computer adventures and concerns of older adults. If you have comments, questions or suggestions for future columns, Email HIM at:

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