Good Video on VoIP Security and Telephony Denial of Service
Jun 5, 2014
Here is a link to a good video on VoIP and SIP security.
Patrick McNeil covers how to hack SIP servers, at service providers and enterprises, to make money. The presentation is useful because it covers why someone might bother to hack these servers, namely:
At the end of the presentation, there is a brief TDoS demo.
Note that another way to make money is call pumping, where the calls are to 1-800 numbers and the attacker gets a share of the revenue, but this arrangement is more difficult to set up.