How To Keep Your Computer Safe

Step 3: Be a Smart Email and Internet User

Even if you use antivirus software, you should not develop a false sense of security that the software will protect you from everything. More than 500 new viruses are discovered each month, and you could be hit before your antivirus software releases an update to protect you. In addition to viruses, your computer could be attacked by a worm (which could be in an email attachment or could be embedded in an email or a Web page – meaning it becomes active when you open the email or visit the infected Web page) or a Trojan horse (a downloadable program that appears to be something “good” – like a game or a screen saver – but contains spyware or damages files on your computer).

But these aren’t the only things you should worry about. The Federal Trade Commission estimates that more than 1 in 10 Americans have fallen victim to fraud, and 55 percent of all fraud reported last year was Internet-related. The most common means of fraud are email or Internet scams.

Any junk email you receive should be treated as if it were a scam, because most of the time, it is. Prize promotions, advance-fee loans, or foreigners promising you riches if you will let them use your bank account are just a few ways others might try to take advantage of you. One advanced means of scamming is known as spoofing or phishing; this is when an email or a fake website tries to deceive you into thinking it is from a business such as eBay, or your bank. Identity thieves may use these to try and trick you into releasing personal information, such as bank account numbers, ATM PINs, or security passwords.

Although they are not as big of a threat as viruses, unwanted advertisement emails (known as spam) can be annoying and can contain scams or phishing attempts, as described above. Many email applications and web-based email (like Yahoo and Hotmail) provide email filters that you can use to keep spam from getting into your inbox. These filters can also reduce the risk of receiving viruses.

How to do it:

Be suspicious of any email you receive that contains an attachment, unless you are expecting it. If you know your sister is emailing you holiday photos, they’re probably safe. But who the email comes from is not always an indication that it is safe. Most people would be suspicious about receiving an email with an attachment from a stranger. However, if someone you know gets a virus on his computer, the virus may pull your email address from his address book and send a virus-laden attachment to you. The virus could come from the person with the infected computer – but it may appear to be coming from someone else, instead. The best courses of action are:
1. If you are suspicious about the email, delete it without opening the attachment. Let's view an example of a suspicious email.
2. The three-letter extension at the end of a file name can sometimes give you a clue about what type of file it is. For example, in something.doc, .doc means it is a Microsoft Word document file. Photo.jpg is a jpg, or a picture. Always be suspicious of attachment with these program extensions: .bat, .exe, .pif, .scr, .vbs, .wsf. However, be aware that some viruses may mask the program extension, so that the attachment appears to be a different file type.
3. If the email comes from someone you know, but you’re not sure about whether the attachment is safe, send that person an email asking if he sent you an attachment and what the attachment is.
4. If you use a web-based email, be sure to run the attachment through the built-in antivirus before opening it. If you use Outlook Express or another email program, be sure to set your antivirus program to automatically scan all incoming emails.
If something sounds too good to be true, it probably is. This is a common example of a fraud email. Think twice before sharing your personal information with anyone who has told you you’ve won a prize. (Did you enter any contests?)
Never follow a link in an email, unless you absolutely trust the sender. The link may appear to be sending you to a legitimate website (such as ebay.com), but in fact is designed to send you to a fake website. And keep in mind that ecommerce and financial company sites never request financial or account information via email and they will never email you an attachment – so any email you receive that does either should be considered suspicious. Even if an email looks legitimate, the sender could have forged the header to make it appear as if the message came from someone else. You should instead directly type the URL to the company’s site into your Web browser window, or contact the company (by email or phone) to verify the email. Here's an example of such a bogus email.
Protect your email address. Spammers often harvest email addresses by scanning chatrooms, searching the Web, and buying online mailing lists. This means that every time you use your email address to register for a website or other online service, you take the risk that your email address will end up in the hands of a spammer. One of the best ways to protect your email address is to keep it private, and the best way to accomplish that is to use two different email addresses: One is your “real” email address – this one you use to send and receive emails from family, friends, coworkers, etc. The second is your “junk” email address – this one you use only to register at websites, to sign up for chat rooms and messageboards, etc. Also, when a website asks for your email address, take a moment to see if: a. is it required for you to provide an email address, b. what privacy protections does the website guarantee (ie, will they sell your email address), and c. is there a way to opt out of receiving future emails.
Never reply to spam, not even with an “unsubscribe” message. Spammers just use your response to confirm that your email address is valid and active – which means you’ll just end up getting more spam.
To learn more about the specific filters available through your email application, use the Help function within your email client. Tutorial videos for several email applications (such as Outlook Express) and web-based email (like AOL and Hotmail) can be found here: http://security.getnetwise.org/tools/filters. (This video does not include audio.)

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Last Updated: 6 January 2005