Mozilla Foundation Security Advisory 2006-28

Security check of js_ValueToFunctionObject() can be circumvented

Announced

April 13, 2006

Reporter

shutdown

Impact

Critical

Products

Firefox, SeaMonkey, Thunderbird

Fixed in

• Firefox 1.5.0.2
• SeaMonkey 1.0.1
• Thunderbird 1.5.0.2

Description

The security check in js_ValueToFunctionObject() can be bypassed by clever use of setTimeout() and the new Firefox 1.5 array method ForEach. shutdown demonstrated how to leverage this into a privilege escalation vulnerability that would allow the installation of malware.

This vulnerability was introduced during Firefox 1.5 development, Firefox 1.0 and Mozilla Suite 1.7 are not affected.

Thunderbird shares the browser engine with Firefox and could be vulnerable if JavaScript were to be enabled in mail. This is not the default setting and we strongly discourage users from running JavaScript in mail.

Workaround

Disable JavaScript until you upgrade to a fixed version.

References

Exploit code and details embargoed during the active update period.

• https://bugzilla.mozilla.org/show_bug.cgi?id=323501
  CVE-2006-1726