Email Attachments and Viruses

1/29/02 - Email Attachments and Viruses

I've preached this over and over again in class, but I'll say it one more time here...NEVER OPEN EMAIL MESSAGES WITH FILE ATTACHMENTS. You never really know if the attachment is really safe.

How do you tell if an email message has an attachment? Typically an email message with an attachment has a paper clipnext to the message in your inbox. Click here to see an example of my Outlook screen. (Note: This screen capture is of Outlook) This should be your first clue that the message may be unsafe (I really wouldn't recommend opening email message with attachments at all! The BadTrans virus spreads itself just by opening or previewing the email message (you don't have to open the actual attachment)).

If you're a risk-taker and you open a message that has an attachment you will notice that there is a box just below the Subject line that says Attachments (Outlook) or Attach (Outlook Express). This box shows the file attachments and the type of file (indicated by the icon) that is attached (the envelope icon means that this is a forwarded email message). Below is a table of some of the attachment icons.

	An executable file. NEVER OPEN an attachment with this icon. Viruses are usually spread via .exe and .com files (program files), this is the icon that represents program files. High risk of viruses.
	This icon is just as dangerous as the .exe icon above. The icon indicates that the file type is unknown. High risk of viruses*.
	Always scan a Word document, .doc, for viruses prior to opening it. Word documents can contain Macro viruses which can be potentially harmful to your system. High risk of viruses*.
	Excel files can also contain Macro viruses which can be potentially harmful to your system. Always scan a Excel document, .xls, for viruses prior to opening it. High risk of viruses*.
	Zip files, .zip, are compressed files (they can contain Word, Excel, Jpeg, Gif, html, or any other file type including viruses). High risk of viruses*.
	A forwarded message. The message contains an attached email message, *.eml (usually a joke or information that someone is forwarding to you). The messages typically have Fw: in the subject line (the message was forwarded from someone else). It is possible for the attached email message to contain a virus.
	A jpeg or a gif image. (These icons may look different on your system.) In Outlook Express jpeg and gif images are automatically inserted as a part of the body of the message. Beware, some viruses have jpg in the filename to try and fool you into thinking that the virus is just a picture. If the attachment has jpeg in the name, but has a program or unknown icon (above) it is probably a virus.
	Someone is sending you a web page link to view. Notice the little arrow on the icon, it indicates a shortcut to a web site and they are usually safe.
	This indicates that an entire web page has been included in the email. Notice that this icon does not have the little arrow. Because web pages can contain potentially harmful code be sure you are familiar with the site before you open the attachment. Tip: When you want to share a web site with someone, it is better to forward the link rather than the entire web page. In Internet Explorer click File > Send > Link by E-mail.

People who create viruses are always trying to come up with new ways to spread their germs. One of the latest viruses MyParty, with a subject line that says: Subject: new photos from my party! has an attachment that looks like this:

At first glance, this looks like an innocent web address www.myparty.yahoo.com, but notice the the icon, it's an *.exe or program file and the extension is .com (a program file). Tricky, eh?? This is a virus in disguise. The virus is spread by someone double clicking the email attachment, the virus executes a program that sends itself out to all of the people in your address book. (Usually your friends!) So you can't even trust email from friends anymore. :( (Please note that your friends do not send viruses to you intentionally, the virus does.) What makes this message even more tempting to open is that the body of the message is:
Body: Hello!
My party... It was absolutely amazing!
I have attached my web page with new photos!
If you can please make color prints of my photos. Thanks!

So suppose you just went to a party at your friend's house on Saturday night and you get this email message from your friend who hosted the party on Monday morning...Wouldn't you be tempted to open it up? I thought so...Don't, it's a virus.

More Virus Tips

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