http://sourceforge.net/projects/vipervast/files/VIPER_VASTbetav2.76.iso/download http://www.hackingvoip.com/sec_tools.html http://www.symantec.com/connect/articles/voip-hopping-method-testing-voip-security-or-voice-vlans http://www.symantec.com/connect/articles/two-attacks-against-voip