Identifying and Preventing Email-Borne Viruses

We’ve all done it- no matter how careful we are, somehow we all manage to pick up a virus at some point. One of the most common ways people get computer viruses is through spam email.

Although a large percentage of spam is easy to identify, some varieties use more subtle and difficult to detect methods. This article will help you identify and avoid many types of email-borne viruses.

Most email-borne viruses come in the form of attachments or web links. Before you click, ask yourself: Do I recognize the person or organization sending me the email? Am I expecting this information? If the answer to either or both of these questions is “no,” think twice before clicking links or downloading attachments.

Even if you recognize the sender, they may have had their account compromised. Read the language of the email carefully before opening links and attachments – most illegitimate email from known email addresses will sound very different from the sender’s usual style. Common giveaways include:
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• Extremely brief messages 
• Notes requesting that you click on the attached file
• Subject Line stating: “Here are the files you requested,” but you do not remember requesting a file from this person.
  
  

Email Attachments:If it is part of your job to accept emails from unknown addresses, you should familiarize yourself with the types of files you are likely to receive as attachments. You can identify the type of file by the letters that appear at the end of the filename.

Generally Safe:    

• PDFs (.pdf): Opens in Adobe Reader or Adobe Acrobat.
• Word Documents (.docx, .doc): Opens in Microsoft Word
• Text Files (.txt) It is unlikely, but you may receive text files as well. These files typically open in Notepad.
  
  

Use Caution:

• Excel Files (.xlsx, .xls): If you do not know the sender and you are not expecting a file, use caution when opening Excel files. Although it is uncommon, they can contain potentially malicious elements.
  
  

Do Not Open Before Confirming With Sender:

• Zip files (.zip): Zip files are compressed folders that, among other things, allow people to send files larger than the typical maximum email attachment size. Although people you know may use zip files to send large attachments, you should always confirm with the sender before downloading and opening this type of file. They can contain malicious attachments that only appear once their contents are extracted.
  
  
• Executable (.exe) Files and other unknown file types: These files are very rarely sent from legitimate sources. They are typically automatically blocked by your spam filter. If you receive one in your email, do not open unless you confirm with the sender via another means of communication – preferably phone, in person, or another form of social media.
  
  

Embedded Links:If you receive an email with a hyperlink, use caution before clicking. You can check the contents of the link by hovering over it with your mouse. The full link address will appear at the bottom of your web browser or next to your mouse pointer.

Below is the full address from a link in an email from MyNewCompany.com. When I hovered over the link with my mouse, the  web address contained the word “mynewcompany,” so it is a safe assumption that this is a legitimate communication. 

If you are still uncertain, you can always navigate to the page yourself. For example, if you get a suspicious email that says it is from your bank, just type www.mybank.com into the address bar instead of clicking on the embedded link. If you don’t find the information from the email on the bank’s website – congratulations! You just successfully avoided email spam.

Stay tuned for our next post, where we will discuss other ways to avoid viruses – and how to remove them if they make it through your best defenses.
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If you have questions or if you need help with virus removal and/or training employees to recognize and avoid viruses, contact us at info@cyberiadsolutions.com - ask about our spam training courses!