As of October 6th, the Bing Bar will no longer be available on Firefox due to a security issue that manifests when running Bing Bar on Firefox. We encourage Firefox customers who’d like to use Bing to use Bing.com as their default search engine through the web browser experience or download the Bing add-on for Firefox here: https://addons.mozilla.org/en-US/firefox/addon/10434/. This issue does not affect Bing Bar customers on Internet Explorer.
All versions of Bing Bar 4.x, 5.x, 6.0 and all related components like Default Manager and SEP are to be disabled via this update. Please note that no additional action is required by customers. Once the update has propagated to all instances and upon the next browser run, the Bing Bar will be disabled and the following is a mock-up of the update message that will appear in the Firefox update window:
For further information, please reference the Micro Knowledge Base article: http://support.microsoft.com/kb/2430460