How do you decide whether to open an email attachment?

How do you know whether it is safe to open a file from the Internet or an email message?How do you decide whether to open an email attachment?Table of ContentsWhat is a computer virus, Trojan or Adaware?* ...........................................................................2Avoiding Computer Viruses in Email Attachments ......................................................................2Minimize your exposure to viruses................................................................................................3What you should know about opening files from the Internet or e-mail.......................................4Does that file have a virus?............................................................................................................4What do you know about that e-mail attachment?.........................................................................4Can I trust every Web site?............................................................................................................5More trustworthy sites tend to… ...............................................................................................6Is it safe to download that file?......................................................................................................6Heed any warnings.....................................................................................................................6Should I send file attachments? .....................................................................................................8For more information see the Technical Services FAQ page....................................................8Table of FiguresFigure 1: Attachments in Outlook Mailbox.......................................................................................3Figure 2: Sample Attachment ............................................................................................................4Figure 3: Downloading from the Internet ..........................................................................................5Figure 4: "Attachments can contain viruses that may harm your computer" ....................................6Figure 5: Attachment warning message.............................................................................................7Figure 6: Carefully exam attachment information.............................................................................7Figure 7: Attachments in Outlook Web Access.................................................................................8Page 1 of 8Attachment may contain a virus

How do you know whether it is safe to open a file from the Internet or an email message?Minimize your exposure to virusesFigure 1: Attachments in Outlook MailboxYou can minimize your chances of falling victim to these malicious programs by following theseguidelines:‣ Install up-to-date anti-virus software on your computer, and download the latest virusdefinitions frequently.‣ Back up important files on your computer.‣ Never send, click, open, save, or run email attachments that you are not expecting. (Beparticularly cautious about executable files, which end with these extensions: .exe, .com, .vbs,.lnk, .pif, .scr, .bat.)‣ If you receive an email attachment from someone you do not know and trust, delete themessage immediately without opening the attachment. If you know and trust the sender,email the person to verify that they meant to send the attachment.‣ Make sure any attachments you send are virus-free. Include a description of the attachmentin the body of the message.© http://help.yahoo.com/us/tutorials/mail/mail/mail_attachments1.htmlPage 3 of 8Attachment may contain a virus

How do you know whether it is safe to open a file from the Internet or an email message?What you should know about opening files from the Internet or e-mailSource: Microsoft Internet Explorer Help SystemThe most common way for computer viruses to spread is through files that you get from theInternet or e-mail.Figure 2: Sample AttachmentSo before you download a file or click an e-mail attachment, consider:Does that file have a virus?You won't know unless you check. Make sure you have an antivirus program installed and that itis up to date and set to scan all incoming e-mail attachments and downloaded files. Keeping yourantivirus program up to date improves its chances of catching the latest known virus.If you do not have antivirus software installed, you should purchase and install an up-to-dateantivirus program to help protect your computer.What do you know about that e-mail attachment?Before you open an e-mail message or attachment, consider these questions:‣ Do you know and trust the sender of the e-mail message? If you get e-mail from a person orbusiness you’ve never heard of before, you should be cautious.‣ Have you exchanged e-mail with this person before? If you get e-mail from someone youknow but have never corresponded with, ask yourself if there is any reason you’re getting thismessage now—especially if the message has a file attachment or contains a link to a Website.‣ Do you have any reason to expect e-mail from this person? If you are surprised to see e-mailfrom this person, be cautious about opening the message.‣ Does the message on the subject line make sense coming from the sender? If the subject lineis just gibberish or nonsense, you’ll be safer if you delete the message.Page 4 of 8Attachment may contain a virus

How do you know whether it is safe to open a file from the Internet or an email message?If the answer to all of the questions above is no, it's probably best to delete the message.If you know the sender of the message but the message looks suspicious, don't hesitate to senda message to the sender asking if they really sent the e-mail to you. It’s much easier to checkbefore you open the message than it is to clean viruses off of your computer.Can I trust every Web site?Not every Internet neighborhood is safe. Be cautious of a Web site if…‣ You were referred to the site by e-mail from someone you don’t know.‣ The site contains objectionable material, such as pornography.‣ The site makes offers that seem too good to be true. Is it just trying to lure you to the site?‣ You are asked to provide a credit card number but there is no indication that the Web siteensures its transactions are secure.‣ The site offers free membership but asks you to provide extensive personal information thatdoes not seem necessary or that you do not want to provide.Figure 3: Downloading from the InternetPage 5 of 8Attachment may contain a virus

How do you know whether it is safe to open a file from the Internet or an email message?More trustworthy sites tend to…‣ Be certified by an Internet trust organization such as BBBonline, TRUSTe, or WebTrust. Lookfor their logo on the site and click the logo to make sure it is authentic.‣ Provide a privacy statement that you can understand and that you are comfortable with.‣ Provide a way to contact the creator or organization—a physical location, phone number, e-mail address, or mailing address.‣ Have a clearly posted return policy (when applicable) that allows you to return themerchandise if you are not satisfied.‣ Offer proof of secure transactions, such as a statement that your credit card information will beencrypted, or a symbol in the browser status area that indicates the transaction is secure.Is it safe to download that file?You can help protect your computer by thinking carefully before you download a file.Figure 4: "Attachments can contain viruses that may harm your computer"Heed any warnings‣ When a Web site attempts to download a file to your computer, Internet Explorer will display amessage about saving, running, or installing the file.‣ If the message contains a yellow caution icon, then the file has been identified as a type thatcould pose a risk.Page 6 of 8Attachment may contain a virus

How do you know whether it is safe to open a file from the Internet or an email message?‣ Below is an example of a warning message regarding an attachment.Figure 5: Attachment warning message‣ Make sure the message shows the file source (publisher name). If the publisher can't beidentified, it is safer to delete the file unless you know for certain who created it.‣ Make sure you completely trust the Web site providing the file.‣ Make sure the file is something you requested or are expecting.Figure 6: Carefully exam attachment information‣ Consider the content. Picture, music, and plain-text files are less likely to be harmful.These file types have names that end with a three-letter extension such as .jpg, .gif, .mp3,or .txt. You should be very cautious with all other file types.Page 7 of 8Attachment may contain a virus

How do you know whether it is safe to open a file from the Internet or an email message?Should I send file attachments?You can send file attachments to others, while following a few helpful steps.‣ Specify in the subject line and/or near the top of the email message that the purpose andcontent of the attachment.‣ Whenever possible, do not send attachments that are executables (identifiable as *.exe).MS Word *.doc can also host viruses. If you can, convert documents into Adobe AcrobatReader documents (*.pdf) before attaching to an email message.Figure 7: Attachments in Outlook Web AccessFor more information see the Technical Services FAQ pageFor more information on combating junk mail, go to the Woodring College of Education TechnicalServices FAQ pages: http://www.wce.wwu.edu/Resources/TechServ/FAQDocs/Page 8 of 8Attachment may contain a virus