A malicious Firefox extension called FirestarterFox is being installed by some of the latest malware variants. This extension hijacks all search requests through Google, Yahoo and Microsoft Live search and redirects them through the Russian site thebestwebsearch.net. This is done with the intention of showing ads on the search results page which presumably make money for the creator of this piece of malware.
Watch out If you ever start Firefox and unexpectedly see a new extension installation dialog you should be wary that you may have malware on your system. This latest one is called FirestarterFox.