Aviv Raff has discovered a weakness in Google Toolbar, which can be exploited by malicious people to conduct spoofing attacks.

The weakness is caused due to an error when handling domains that are being displayed in the Custom Button Installer dialog. This can be exploited to spoof the origin of a custom button and the domain information in the "privacy considerations" section via a specially crafted xml file in combination with a redirector page.

The weakness is confirmed in Google Toolbar version 4.0.1601.4987 for Internet Explorer. Other versions may also be affected.

Solution
Do not rely on information in the Custom Button dialog when installing custom buttons.

Provided and/or discovered by
Aviv Raff

Changelog
Further details available to Secunia VIM customers

Original Advisory
http://aviv.raffon.net/2007/12/18/GoogleToolbarDialogSpoofingVulnerability.aspx

Deep Links
Links available to Secunia VIM customers