Vulnerability Note VU#113192

Mozilla allows signed scripts calling "enablePrivilege" to change contents of a "grant" dialog

Overview

A vulnerability in the way Mozilla and its derived programs display dialogs in some circumstances could allow a remote attacker to install and run software on a vulnerable system.

I. Description

The Mozilla web browser and related Mozilla products support the ability to run signed scripts supplied in HTML email or webpages. A signed script can request expanded privileges that give it access to restricted information and abilities by using the enablePrivilege method. A deficiency in the way that these products create dialog boxes via enablePrivilege allows a malicious script to supply a string including spaces and normal text for the dialog box. A malicious signed script requesting enhanced abilities could construct the request in a way that possibly fooled the user into thinking the privilege requested was inconsequential while actually obtaining explicit permission to run and install software. The user would still be required to explicitly click "Ok" in the grant dialog for exploitation of this issue to be successful.

II. Impact

By convincing a victim to accept a signed script, a remote attacker may be able to install and run software with the privileges of the user running an affected program.

III. Solution

Upgrade to a fixed version of the affected software

The Mozilla Project has released new versions of the affected software that include patches for this vulnerability. Please see the Systems Affected section of this document for more information.

Workarounds

Users who are unable to upgrade to a patched version of the software are encouraged to apply the following workarounds:

Disable Javascript
Never grant enhanced abilities of any kind to untrusted web pages (this workaround comes from from the Mozilla project advisory about this issue)

Systems Affected

Vendor	Status	Date Updated
AOL Time Warner	Unknown	20-Sep-2004
Conectiva	Vulnerable	26-Oct-2004
Gentoo	Vulnerable	26-Oct-2004
Mozilla	Vulnerable	17-Sep-2004
NETscape Communications Corporation	Unknown	20-Sep-2004
SuSE Inc.	Vulnerable	26-Oct-2004

References

http://bugzilla.mozilla.org/show_bug.cgi?id=253942
http://secunia.com/advisories/12526/
http://www.securitytracker.com/alerts/2004/Sep/1011317.html
http://www.securitytracker.com/alerts/2004/Sep/1011318.html

Credit

Information about this issue was originally published by the Mozilla Project. The Mozilla Project, in turn, credits Jesse Ruderman with the discovery and reporting of this issue

This document was written by Chad R Dougherty.

Other Information

Date Public	09/14/2004
Date First Published	09/17/2004 02:08:26 PM
Date Last Updated	10/26/2004
CERT Advisory
CVE Name
US-CERT Technical Alerts
Metric	6.21
Document Revision	8

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