Check out Rich's recent entry about the Feds "Raining on Digium's Parade" by coming out with a statement about how Asterisk-based systems may be more susceptible to certain attacks, like vishing, spoofing, etc... via VoIP.
Visit the IC3 for the original complaint.
For the complete response from Digium's Asterisk Community Director, John Todd, be sure to read his blog entry titled SIP Security and Asterisk.
I posted a short summary article here.
