After doing some research on the net, since the malware has been embedded into the android OS by phone manufacturers, removal is impossible by factory reset. Rooting and installation of busy box to access system files to manually delete it will render your smart phone unusable! It's the same like deleting core system files from your windows OS system.
The only way to remove malware that's embedded into your system OS is to flash a new rom. This is not an isolated case. Google the trojan name and you will find similar complaints.