CMSniff will allow anyone on a cable connection to sniff out MAC Address information along with users TFTP Server, Client IP and even configuration files! It works by sniffing out the broadcast packets from your cables server from what ever IP address you are assigned to. What can you do with something like this? Well, given you have the right firmware for your modem, you can change your HFC Mac to someone elses to clone them and get free cable internet or even download their config file to uncap your modem to faster speeds.
