Rule #1 - Don't open an email attachment unless you know what it is and who it is from.
Most viruses spread by emails come one of two ways - in an attachment, or through a link to an infected website. Either way, you the user have to click on it to activate it. So don't! Almost all the email attachments we care about we expect or know what it is. You do not have to open every email you get, and you do not have to look at every attachment. Open only those that pass the test of Rule #1.
We had three clients in 2009 become infected with a particularly nasty virus that caused some data loss. At first glance, the poisoned email looked like it came from Fed Ex. The email said the attachment had order details in it. None of the targets recognized what the Fed Ex email was talking about, so of course they clicked on the Order Details attachment to find out more... ouch! Our clients all used Fed Ex fairly frequently - how could they have avoided this nasty mail bomb? Rule #2...
Rule #2 - If you know who it it's from, but don't know what it is, open the email in "Safe Mode".
If you use MS Outlook, you can move the email to your Junk Mail folder and open it from there. Junk Mail turns off everything except text - no pictures, no working links - nothing but text. In fact, if there are embedded or disguised links, it changes the link to text and you can read where it really goes to - not where the original email said it would go to.
(If you are using webmail, open the email in text format, not HTML format. And, don't open the attachment. It's safe up on the web server as long as you don't open it.)
One thing Outlook's Junk Mail will not let you do - you can't open any attachments. If you have read the email in Junk Mail, looked for hidden links, and you still don't know whether or not to trust it - pick up the phone and call the sender. If the sender is not a business you can find, or someone you know, forget about the email. Leave it in your Junk Mail folder and blaze on with your day. This mystery is probably not worth your time to solve.
See related article - Should I or should I not hit the "unsubscribe" button?
