Routing Information Protocol (RIP) is the most common routing protocol used today. Unfortunately, older versions of RIP are non-authenticating. Routers using RIP send their routing tables to each other at predetermined intervals.

If a router receives a table that has a shorter route to a remote network, it will change its own routing tables to use that newly discovered route. Since there is not an authentication process, hackers can send false routes to your router, causing it to change its routing tables from legitimate routes to illegitimate ones.