Two new vulnerabilities have been found in Cisco call manager servers and VoIP telephones. One vulnerability can DoS CUCM server's with the CTI manager service. Not only can you interrupt phone calls though, you can also listen in on them too by exploiting the RIS data collector.

Since the ports for CTI manager and RIS data collector are not user configurable there is currently no easy way to secure your network. The only way you can secure it is by only allowing certain IP address to connect and disallowing any others.