Vulnerability Note VU#911004

Mozilla Firefox fails to properly handle the "XPCNativeWrapper(window).Function(...)"

Overview

Certain Mozilla products contain a cross-site scripting vulnerability because of a vulnerability in the XPCNativeWrapper function.

I. Description

XPCNativeWrapper

Per Mozilla, XPCNativeWrapper is a way to wrap up an object so that it is safe to access from privileged code. It is used to allow chrome code to access DOM objects.

The Problem

An attacker can use the XPCNativeWrapper function to inject script into a browser window that may be in a different domain. This violates the Netscape same-origin policy.

II. Impact

By convincing a victim to view an HTML document (web page), an attacker could evaluate script in a different security domain than the one containing the attacker's document. The attacker could read or modify data in other web sites (read cookies/content, modify/create content, etc.). If the script is evaluated with chrome privileges, an attacker could execute arbitrary commands on the user's system.

III. Solution

Upgrade

This issue is addressed in the 1.5.0.5 updates to Mozilla Firefox and Thunderbird, and the 1.0.3 version of Seamonkey. Refer to Mozilla Foundation Security Advisory 2006-54 for more details.

Disable JavaScript

For instructions on how to disable JavaScript in Firefox, please refer to the Firefox section of the Securing Your Web Browser document. JavaScript is not enabled by default in Mozilla Thunderbird.

Systems Affected

Vendor	Status	Date Updated
Mozilla, Inc.	Vulnerable	1-Aug-2006

References

http://www.mozilla.org/security/announce/2006/mfsa2006-54.html
https://bugzilla.mozilla.org/show_bug.cgi?id=338523
http://secunia.com/advisories/19873/
http://secunia.com/advisories/21216/
http://www.securityfocus.com/bid/19181

Credit

Thanks to Mozilla for reporting this vulnerability. Mozilla in turn thanks shutdown.

This document was written by Ryan Giobbi.

Other Information

Date Public	07/25/2006
Date First Published	08/01/2006 04:12:15 PM
Date Last Updated	02/09/2007
CERT Advisory
CVE Name	CVE-2006-3810
US-CERT Technical Alerts
Metric	2.74
Document Revision	14

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Produced 2006 by US-CERT, a government organization
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