Firefox Virus
A few anti-virus firms are reporting that there is a virus spreding using the extentions feature of Firefox. The trojan has been named FormSpy and Sophos has been dubbed Troj/FireSpy-A. It captures information from the browser (like passwords and bank details) and send them to a remote computer. The trojan also comes with a file that Windows can execute that also records ICQ, POP3, IMAP and FTP passwords. The trojen pretends to be the legitimate Numberlinks extention.
You should remember this virus will only get onto your computer if you let it, it does not exploit a weekness in Firefox.