Vulnerability Note VU#471361

Microsoft Internet Explorer cross-domain frame race condition

Overview

Microsoft Internet Explorer contains a race condition that results in a cross-domain violation.

I. Description

Internet Explorer uses a cross-domain security model to maintain separation between browser frames from different sources. This model is designed to prevent code in one domain from accessing data in a different domain. The Internet Security Manager Object determines which zone or domain a URL exists in and what actions can be performed.

A race condition in Internet Explorer may allow an attacker to evade the cross-domain security model. Note that Internet Explorer 6 and Internet Explorer 7 are affected by this vulnerability.

II. Impact

A website in one domain has the ability to access information in another domain. The website may also be able to execute scripts or take other actions that are permitted in the other domain.

III. Solution

We are currently unaware of a practical solution to this problem.

Do not follow unsolicited links

In order to convince users to visit their sites, attackers often use URL encoding, IP address variations, long URLs, intentional misspellings, and other techniques to create misleading links. Use caution when clicking on unsolicited links received in email, instant messages, web forums, or internet relay chat (IRC) channels. Type URLs directly into the browser to avoid these misleading links. While these are generally good security practices, following these behaviors will not prevent exploitation of this vulnerability in all cases.

Disable Javascript

Disabling Javascript may mitigate this vulnerability. Instructions for disabling javascript can be found in the Securing Your Web Browser document.

Systems Affected

Vendor	Status	Date Updated
Microsoft Corporation	Vulnerable	5-Jun-2007

References

http://archives.neohapsis.com/archives/fulldisclosure/2007-06/0026.html
http://msdn2.microsoft.com/en-us/library/ms537183.aspx
http://msdn2.microsoft.com/en-us/library/ms537186.aspx
http://www.cert.org/tech_tips/securing_browser/#Internet_Explorer
http://www.antiphishing.org/consumer_recs.html

Credit

This issue was reported by Michal Zalewski on the Full-Disclosure mailing list.

This document was written by Ryan Giobbi.

Other Information

Date Public	06/04/2007
Date First Published	06/05/2007 09:24:29 AM
Date Last Updated	06/07/2007
CERT Advisory
CVE Name
Metric	0.00
Document Revision	13