MS02-005: Patch Is Available for the Buffer Overrun in HTML Directive Vulnerability

A buffer-overrun vulnerability exists in Internet Explorer 5.5 and 6. By creating a specially formed Web page and either posting it on a Web site or sending it to a user as an HTML e-mail message, an attacker might be able to take action on another user's computer, including adding, creating, or deleting files; communicating with Web sites; or reformatting the hard disk.

The vulnerability is subject to several mitigating factors:

• The email-message-borne attack scenario would be blocked if the user were using any of the following programs: Microsoft Outlook 97, Microsoft Outlook 98, or Microsoft Outlook 2000 with the Outlook Email Security Update (http://office.microsoft.com/Downloads/2000/Out2ksec.aspx) installed; Microsoft Outlook 2002; or Microsoft Outlook Express 6.
• The Web-based attack scenario could be blocked by judicious use of the Internet Explorer security zones mechanism.
• An attacker who successfully exploited this vulnerability could gain the same privileges as the legitimate user, but not system-level privileges. If the user had few permissions on the computer, the attacker would gain only those permissions. If the user had more privileges, the attacker would gain those permissions as well.

This vulnerability results because of an unchecked buffer in the implementation of an HTML directive (http://msdn.microsoft.com/en-us/library/cc507736.aspx) that allows a Web page to incorporate a document. By creating a Web page that invokes this directive in the right way, an attacker could overrun the buffer and cause any code to run on the user's computer.

• Internet Explorer 6
• Internet Explorer 5.5 Service Pack 2
• Internet Explorer 5.5 Service Pack 1

Internet Explorer 6

To resolve this problem, obtain the latest service pack for Internet Explorer 6. For additional information, click the following article number to view the article in the Microsoft Knowledge Base: The update for this problem is included in the "February 11, 2002, Cumulative Patch for Internet Explorer." For additional information about how to obtain this patch, click the article number below to view the article in the Microsoft Knowledge Base:

Internet Explorer 5.5 Service Pack 2

A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that you determine are at risk of attack. Evaluate your computer's physical accessibility, network and Internet connectivity, and other factors to determine the degree of risk to your computer. See the associated Microsoft Security Bulletin (http://www.microsoft.com/technet/security/bulletin/ms02-005.mspx) to help determine the degree of risk. This fix may receive additional testing. If your computer is sufficiently at risk, Microsoft recommends that you apply this fix now. Otherwise, wait for the next Internet Explorer 5.5 service pack that contains this fix.

To resolve this problem immediately, download the fix by following the instructions later in this article or contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:NOTE: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

The update for this problem is included in the "February 11, 2002, Cumulative Patch for Internet Explorer." For additional information about how to obtain this patch, click the article number below to view the article in the Microsoft Knowledge Base:

Internet Explorer 5.5 Service Pack 1

A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that you determine are at risk of attack. Evaluate your computer's physical accessibility, network and Internet connectivity, and other factors to determine the degree of risk to your computer. See the associated Microsoft Security Bulletin (http://www.microsoft.com/technet/security/bulletin/ms02-005.asp) to help determine the degree of risk. This fix may receive additional testing. If your computer is sufficiently at risk, Microsoft recommends that you apply this fix now. Otherwise, wait for the next Internet Explorer 5.5 service pack that contains this fix.

To resolve this problem immediately, download the fix by following the instructions later in this article or contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:NOTE: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

The update for this problem is included in the "February 11, 2002, Cumulative Patch for Internet Explorer." For additional information about how to obtain this patch, click the article number below to view the article in the Microsoft Knowledge Base:

Internet Explorer 6

Microsoft has confirmed that this problem may cause a degree of security vulnerability in Microsoft Internet Explorer 6. This problem was first corrected in Internet Explorer 6 Service Pack 1.

Internet Explorer 5.5

Microsoft has confirmed that this problem may cause a degree of security vulnerability in Microsoft Internet Explorer 5.5.

For more information about this vulnerability, visit the following Microsoft Web site: For additional information about the "February 11, 2002, Cumulative Patch for Internet Explorer", click the article number below to view the article in the Microsoft Knowledge Base: