Internet Explorer Vulnerability Affects the Displayed URL for a Web Page

A vulnerability exists in Internet Explorer 5.01 and 5.5 that could make it possible for an attacker to make it appear that content from his or her Web site originated from another site. If the other site were trusted by the user, the attacker might be able to persuade the user to provide sensitive or personal information. It would be possible for the attacker's site to establish a Secure Sockets Layer (SSL) session that would appear to confirm that the content is genuine.

There are two significant limitations on the scope of this vulnerability:

• This vulnerability does not provide a way to actually cause users to arrive at the attacker's site--it only provides a way to pose as the legitimate site after visitors arrive there.
• The vulnerability would likely only enable the attacker to convincingly spoof a single page on the target Web site.

The vulnerability occurs because it is possible for a browser window to display another site's URL (or Web address) in the Address box. In addition, it is possible to establish an SSL session with another site to provide convincing proof that the URL is the correct one.

For additional information about what is fixed by this patch, click the article number below to view the article in the Microsoft Knowledge Base:

Internet Explorer 5.5

To resolve this problem, obtain the latest service pack for Internet Explorer version 5.5. For additional information, click the following article number to view the article in the Microsoft Knowledge Base: For your convenience, the individual update is also available:

The following file is available for download from the Microsoft Download Center:
For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base: Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help to prevent any unauthorized changes to the file. The English version of this fix should have the following file attributes or later: NOTE: This patch requires Internet Explorer 5.5 Service Pack 1.

Internet Explorer 5.01

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/MS01-027.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 5.01 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 following file is available for download from the Microsoft Download Center:
For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base: Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help to prevent any unauthorized changes to the file. The English version of this fix should have the following file attributes or later: NOTE: This patch requires Internet Explorer 5.01 Service Pack 2.

Internet Explorer 5.5

Microsoft has confirmed that this problem may cause a degree of security vulnerability in Internet Explorer 5.5. This problem was first corrected in Internet Explorer version 5.5 Service Pack 2.

Internet Explorer 5.01

Microsoft has confirmed that this problem may cause a degree of security vulnerability in Internet Explorer 5.01 and Internet Explorer 5.01 Service Packs 1 and 2.

For more information about this vulnerability, see the following Microsoft Web site: