Prevent Viruses
PREVENTING THE SPREAD OF VIRUSES
There are a few things that you can do to prevent getting a computer virus or spreading a virus:
- Install Anti-virus software
(You can get free A/V software for home use here: www.avg.com) - Keep the virus definitions up-to-date
- Use common sense when dealing with attachments:
- Do not open UNSOLICITED e-mail attachments
- If you did not EXPRESSLY ask for the file, then it
could be a virus
- If you did not EXPRESSLY ask for the file, then it
- Learn to identify the signs of a potential virus
- Look for signs that it might be a virus by checking the
file extension ("good" extensions vs. "bad" extensions) - Read the body of the message looking for generic
statements such as lack of names, signatures, etc.
- Look for signs that it might be a virus by checking the
- Verify suspect attachments
- Scan the file with UP-TO-DATE definitions
- Call the sender
- Do not open UNSOLICITED e-mail attachments
- Prove that you are the author of the e-mail
- Include some text in the body of the message that
indicates that you INTENDED to send the message
such as your name, email address, extension, etc.
- Include some text in the body of the message that
- Avoid sending attachments in the first place
- COPY & PASTE any text into the body of your
e-mail message instead of attaching the file
- COPY & PASTE any text into the body of your
Following these simple steps can prevent a virus from spreading. Remember, many of these viruses are designed to automatically forward a copy of themselves to EVERYONE in your address book. This means that any virus is more than likely going to come from someone you know or have had e-mail correspondence with in the past.
Identifying Potential Viruses in E-mail Attachments
Below is a typical screenshot from MS Outlook / Outlook Express. Whenever you receive an attachment, there is generally a picture of a paper clip. Single clicking the paper clip reveals that there are 2 files attached.
Notice that the attachment above appears to be a Word Document because of the .doc extension. However, the icon does not appear to be a typical MS Word icon. The typical MS Word icon is a picture of a blue ‘W’, as shown below (at left):
"Good Attachment" vs. "Bad Attachment"
Notice how the attached file in the e-mail above is called “The Pillarbanquet wine.doc” but has a different icon (depicted above right). In this case, the file is really a batch file, which contains potentially dangerous commands. The entire file name of the above file is "The Pillarbanquet wine.doc.bat".
If you clicked on this icon, any commands that are contained within would be executed, including DELETING ALL OF YOUR FILES or REFORMATTING YOUR HARD DRIVE.
Depending on how your computer is configured, it may not be set to show file extensions or extensions of registered files or system files. This means that you may never see certain types of extensions (.bat, .com, .exe, .pif, etc.).
"Good" Files
Typically, “good” attachments will have a picture of their associated program, such as MS Word, Excel, Acrobat Reader, etc.
A word of caution: Even "good" files can contain viruses. There are some macro viruses that are embedded in MS Office documents (Word, Excel, etc.). The best bet is to always make sure that your virus definitions are up-to-date.
"Bad" Files
There are a number of files that can cause problems. Anything that ends in .bat, .com, .exe, .scr, .vbs, .lnk ,pif can cause external commands to be run. Below is a sample of what the icons might look like:
Another word of caution: These are not the only types of files that can cause damage. There are others that I have not listed.
Trying to Determine Whether an E-mail is Legitimate
Notice how the text of the above e-mail is very generic. The message body states:
Hi! How are you?
I send you this file for your advice
See you later. Thanks
It is not "signed" by the sender, nor does it include the recipients name in the body.
An Example of a Good E-mail:
In the example below, notice that I include the recipients name (Bill) and my own name (Dave) in the BODY of the message. I also include the name of the attached file, plus my phone number. Hopefully, this proves to Bill that I was the author of the message and that I intended to send it.
My recommendation is to try to avoid sending attachments if possible. Copy & paste any text from one document into the body of an e-mail. If you need to send an attachment, always include some information that identifies you and assures the recipient that you intended to send the file (such as the recipients' name & why you are sending it to them).
Following these guidelines can help prevent you from getting a virus, which in turn, helps prevent the spread of viruses.