If you are running any Cisco IP Phones in your Network I would recommand to watch this video from
the 29C3 conference:
Hacking Cisco Phoneshttp://www.youtube.com/watch?v=f3zUOZcewtA
Not really good to hear that Cisco is not doing much to get their devices more secure, had expected
that the Cisco TAC would have spend more attention to the Hacker community.