How to use IK or Ctrl Rig to fix feet not reaching floor?

Hi I have some mocap. Because of reasons, the feet of the character on some steps don’t reach the floor. Is there a some method of using an IK Rig to allow me to hand animate this a bit?
I figure I would find the lowest point, then pull the foot down, keyframe - the IK rig helping pull the rest of the leg and so on. Then I put in zero keyframes around it my keyframe to ease back to the anination