To help protect you against most viruses spread via attachments in e-mail, Microsoft has introduced a significant security enhancement for Outlook® 98 and 2000 — the Outlook 2000 SR-1 E-mail Security Update and the Outlook 98 E-mail Security Update. This security update provides protection from most viruses, such as the ILOVEYOU and Melissa viruses, as well as other viruses that spread themselves through e-mail, or worm viruses that can replicate through Outlook. This update limits certain functionality in Outlook to provide a higher level of security; it was not created to address a security vulnerability within Outlook. This update provides unprecedented security protection for Outlook and Microsoft encourages all users of Outlook 2000 and Outlook 98 to install the appropriate update for their version of Outlook.

Important   The Outlook 2000 SR-1 E-mail Security Update requires that you first install Office 2000 Service Release 1a (SR-1a) (which includes the original Office 2000 SR-1 update and the Office 2000/Windows 2000 Registry Repair Utility). To ensure the integrity of your Office 2000 installation, the Outlook 2000 SR-1 E-mail Security Update requires access to the Office CD or your network installation location during the installation process. If you have installed more than one version of Office 2000 on your machine (for example, if you installed Office 2000 Small Business Edition and then later installed Office 2000 Professional Service Release 1), all of the installed versions of Office 2000 must be updated to Service Release 1 level before you install this update. If you are not certain, install the Office 2000 Service Release 1a (SR-1a) to correctly update your installations of Office 2000 before you install this update.

The Outlook E-mail Security Update provides the following security measures:

• E-mail attachment security prevents users from accessing several file types when sent as e-mail attachments. Affected file types include executables, batch files, and other file types that contain executable code often used by malicious hackers to spread viruses.
• Object Model Guard prompts users with a dialog box when an external program attempts to access their Outlook Address Book or send e-mail on their behalf, which is how insidious viruses such as ILOVEYOU spread.
• Heightened Outlook default security settings increase the default Internet security zone setting within Outlook from "Internet" to "restricted sites." In addition, active scripting within restricted sites is disabled by default. These security features help protect users from many viruses that are spread by means of scripting.

Once installed, this update will affect certain functionality within Outlook, and may also have an impact on the interaction of some third-party software programs with Office. For more information before installing the update, read the Microsoft Knowledge Base article (Q262634) OL2000: Known Issues with the Outlook E-Mail Security Update.
System administrators should read the Knowledge Base article (Q263297) OL2000: Administrator Information About the Outlook E-mail Security Update for information about customizing the E-mail Security Update.

Certain e-mail attachments are unavailable

Once you install this update, you will not be able to access attachments with file types that could run executable code or change settings on a computer —  actions that could allow a virus to spread. These file types are known as Level 1 security files. 

Level 1 security files   Level 1 security files (restricted access in Outlook) are files that may contain executable code themselves, or may contain links to other files that contain executable code that could execute a virus on your computer. Level 1 file types include program files (.EXEs, .COMs), script modules and files (.BASs, .VBSs, .JSs), Internet links (URLs, .ISNs), and shortcuts to files (.LNKs, .PIFs). For a list of these file types, see the Outlook E-mail Security Update — Frequently Asked Questions.

Level 2 security files   File types on the Level 2 security list must be saved to disk before they can be opened; the files cannot be opened directly from within Outlook. There are no files types on the Level 2 security list by default, but file types can be added to the list by system administrators. For more information, see the Knowledge Base article (Q263297) OL2000: Administrator Information About the Outlook E-mail Security Update.

Receiving a restricted attachment

If you receive a message that contains an attachment that cannot be accessed, your Inbox will display the paperclip in the attachment column to let you know that the message has an attachment. When you open the message, the attachment will not be available and the following will be displayed at the top of the message:

On the File menu, the Save Attachments command and the View Attachments command on the shortcut menu will not be available for this message. If you receive a message with multiple attachments, any of the unsafe attachments will not be accessible, but other attachments will be retained. When you open the message, you will see the same warning as above, but any attachment not affected by the update will be available to you. Save Attachments and View Attachments can be used for the safe attachment.

Sending attachments

When you attach a file to e-mail, the update checks the file type when you send the message. If the file type is on the list of restricted files, you will be warned that other Outlook users may not be able to open the attachment. If you click Yes, the message is sent with the attachment. If other users have this update installed, the attachment will be inaccessible. If you click No, the message will be returned to you for editing, which will involve removal of the attachment.

Programs are prevented from sending mail without your permission

The Outlook 2000 SR-1 E-mail Security Update changes the behavior of some Outlook automation functionality. Since viruses can spread by sending copies of e-mail messages to people listed in your Address Book, this update changes Outlook functionality so that programs cannot automatically access your Address Book or Contacts list, or send messages on your behalf. In either case, Outlook will prompt you, ensuring that Outlook can't be used to distribute e-mail without your permission.

For example, if code attempts to access your Address Book in Outlook, a warning appears. You can either allow the program access for this instance, or you can select the Allow access for checkbox and specify an amount of time up to 10 minutes. If you do not want the program to access your Address Book, click No. 

Outlook security settings are set to Restricted Sites by default

Functionality differences with Microsoft Office 2000 MultiLanguage Pack

For complete Outlook E-mail Security Update functionality when you are using an Office 2000 MultiLanguage Pack, you will need Office 2000 Service Release 1 (or Office 2000 Service Release 1a (SR-1a)) the Outlook 2000 SR-1 E-mail Security Update, the Office 2000 MultiLanguage Pack Service Release 1 for the language you are using, and the Outlook 2000 SR-1 E-mail Security Update for the MultiLanguage Pack you are using. The Office 2000 MultiLanguage Pack Service Release 1, and the Outlook 2000 SR-1 E-mail Security Update for the MultiLanguage Pack are not yet available; if you install this update without these two MultiLanguage Pack updates, the following functionality is affected when using the MultiLanguage Pack:

• If you receive an e-mail with a Level 1 attachment, the name of the blocked file will not appear at the top of the message, and you will not be able to see or access the attachment within the message.
• When you send an attachment with a Level 1 file type extension, you will not receive a message warning you that other Outlook recipients may not be able to access this type of attachment.
• You will not be prompted to allow programmatic access to your Address Book or Contacts list. Since viruses can spread by sending copies of e-mail messages to people listed in your Address Book, access to the book is denied. This may cause error messages to appear when using other Office programs or when synchronizing with handheld PCs.
• You will not receive a message asking you to allow a program to send an e-mail using the Outlook Visual Basic® Application command, Item.Send. All programmatic access to this command is denied.

Since the Office 2000 MultiLanguage Pack Service Release 1 and the Outlook 2000 SR-1 E-mail Security Update for the MultiLanguage Pack are not yet available, subscribe to the Microsoft Office Auto Update Notification service to be notified by e-mail when they are released.

The Microsoft Office 2000 English Language Pack

The English Language Pack lets you change your user interface and Help to English. If you are using the Office 2000 English Language Pack and need to use this update, you must have installed Office 2000 Service Release 1 (or Office 2000 Service Release 1a (SR-1a)) and the Office 2000 English Language Pack Service Release 1 before you install the Outlook 2000 SR-1 E-mail Security Update. If the English Language Pack Service Release 1 is installed after you install this update, e-mail security functionality is the same as with the MultiLanguage Pack listed above. To prevent limited functionality, be sure to install the Outlook 2000 SR-1 E-mail Security Update after you have installed Office 2000 SR-1 and the Office 2000 English Language Pack Service Release 1.

More information

For additional information about the ILOVEYOU virus, read Information on the VBS/Loveletter Virus.

For more information about the security update, read the Microsoft Knowledge Base article (Q262631) OL2000: Information About the Outlook E-mail Security Update. 

If you are a system administrator, read Knowledge Base article (Q263297) OL2000: Administrator Information About the Outlook E-mail Security Update for information about customizing the E-mail Security Update. System administrators can download the Outlook 2000 SR-1 Security Update Administrative Tools from the Customizing the Outlook 98/2000 E-mail Security Update page.

The Microsoft Knowledge Base article (Q262701) OL2000: Developer Information About the Outlook E-mail Security Update contains additional information about Outlook automation changes. 

After you have installed the update, you can learn more about e-mail security by typing virus protection, e-mail security, or unsafe attachments in the Office Assistant or on the Answer Wizard tab in the Outlook 98/2000 Help window, and then clicking Search.

Once the update is installed you can read troubleshooting information about the Outlook E-mail Security Update by typing troubleshoot e-mail security or troubleshoot virus protection in the Office Assistant or on the Answer Wizard tab in the Outlook 98/2000 Help window, and then clicking Search.

For additional information about software security, take a look at the Office Update Security and Microsoft Office Focus.