In this guide, you will learn how to get Sure Footed in Warframe. You have to follow all the instructions carefully to get it.
Sure-footed can drop as a reward for killing grineer bombard, which can spawn in some mid and most higher level grineer missions. The two places you can mainly go to farm for bombards is either ceres or the kuva fortress, and you have to run missions with lots of enemies spawns in them, so endless missions, mobile defense, etc.
Sure-footed has a very low drop rate from the bombards, so it will likely take you a while farming for the mod before you get it unless you get lucky.