We know Mozilla Firefox is the most secured Open source web browser. It allows many simple application and scripting support through its Add-Ons. Most of the Add-ons are implemented by third parties, so that it may have some dangerous contents like Trojan. But during the testing, it will be caught. But there are few exceptions in this.
2 days ago Mozilla blog has announced that two of the Add-ons are having Trojan codes. They are Sothink Web video downloader version 4.0 and all the versions of Master Filer. They are having Win32.LdPinch.gen and Win32.Bifrose.32.Bifrose Trojan respectively. These are fully focussing on windows users. Now both of them are removed from AMO.
If you are using this Add-on & After hearing this news, you are trying to uninstall this to prevent your PC means, That's impossible.. because only the Add-on will be removed while uninstalling & not the trojan. So that Mozilla has suggested some Antivirus software's they are given below:
Antiy-AVL : http://www.antiy.net/
Avast : http://www.avast.com/index
IKarus : http://www.ikarus-software.at/
McAfee : http://www.mcafee.com/us/default.asp
Norman : http://www.norman.com/home/en
I think only AVG and Avira will be free & others may have trials to use. select a best one that fits you..