Cisco UBR interface with PHP

I have an idea that I wanted to throw out there. I have a cable ISP plant that I am trying to help with a project. They are using Cisco 7114 UBRs to connect their cable modems with their Internet backbone - this device assigns it a dhcp address and associates it with the modems MAC address. It does a lot more than that but that is all I am concerned with. I want to see if I can write a script that will constantly execute the command "show ip arp" which will return the current routing table with the MAC and IP address (dhcp). I can foresee two problems so far, one is that you have to have enable mode access to run this function and two, I would fear creating a security loophole by running an enabled function all of the time. Can I get your thoughts on this? thanks, Doug