The latest sign that malware writers are refining attacks on mobile devices comes from Mabir-A, a new worm capable of infecting specific devices through clever social engineering and the use of both Bluetooth technology and multimedia (MMS) messages. F-Secure also warned of a new Trojan called Fontal-A. Fontal-A is a Symbian Series 60 Trojan that installs a corrupted file that damages the applications manager, preventing the installation of any new applications. F-Secure said the Trojan then causes the phone to fail to reboot. If the user tries to reboot the infected phone, it will be permanently stuck in reboot and must be disinfected before it can be used. F-Secure said the only known method of repairing the phone is to use the reformat key combination, which causes the phone to lose all data.