NOTE: As with any tool, it can be misused. Only use tools such as this on networks you own or have received explicit, written permission to test on. I recommend using VirtualBox and GNS3 in order to give you a safe environment to play.
Python program to redirect unauthenticated HSRP (Cisco Hot Standby Redundancy Protocol) to wherever the attacker chooses.
More details here: http://systems-co.blogspot.com/2015/01/simple-python-owning-unauthenticated.html