Dealing With the Klez Virus

Instructions for Disabling the Microsoft Outlook or Outlook Express Preview Panes

The Klez virus is spreading very rapidly. The SANS computer security group estimates that more than 7% of the computers in the world have been infected. It has infected some of the School Board's systems, including some of our file servers.

One of the reasons this virus is spreading so rapidly is that, under certain circumstances, the Klez virus can infect your computer even if you DO NOT open infected e-mail attachments. Some versions of Microsoft Outlook and Outlook Express can be triggered to automatically execute an e-mail attachment, just by viewing the e-mail. This can happen even if you only view the e-mail in the computer's Preview Pane. To protect your computer, please take the following steps IMMEDIATELY.

Microsoft Outlook | Outlook Express | The Preview Pane | How to Spot a Klez-Infected E-mail

If you use Microsoft Outlook...

  1. Start Outlook.
  2. If the Preview Pane is visible, click the View Menu, then click the Preview Pane menu item. This will hide the Preview Pane.
  3. With the Preview Pane hidden, you can delete suspect e-mail messages without displaying them in the Preview Pane itself. This eliminates the possibility that your computer can be infected just by previewing an infected e-mail.

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If you use Outlook Express

  1. Start Outlook Express.
  2. If the Preview Pane is visible, click the View Menu, then click the Layout menu item to display the Layout options dialog box.
  3. Uncheck the Preview Pane option on the Layout options dialog box.
  4. Click OK
  5. With the Preview Pane hidden, you can delete suspect e-mail messages without displaying them in the Preview Pane itself. This eliminates the possibility that your computer can be infected just by previewing an infected e-mail.

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What does the Preview Pane look like?

This screen shot below shows Microsoft Outlook with the Preview Pane enabled. When you click the message in the Inbox, the Preview Pane, located just below the Inbox, displays the first part of the e-mail message. Certain versions of Microsoft Outlook and Outlook Express can be triggered to automatically infect your computer with the Klez virus, just by viewing an infected e-mail in the Preview Pane. Use the instructions above to turn off your Preview Pane.

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How to spot a Klez-infected e-mail

Many Klez-infected e-mails arrive with a subject line from the following list:

Known random words include:

It is also very difficult to tell where the infected e-mails come from, because the Klez virus substitutes a different sender in the sender field of the infected e-mails it automatically generates. This means that you may get infected e-mails that appear to come from people whose computers are virus-free.

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