Apparently it's for a one year deal, and given our cap situation I doubt it's big money.
I can't fault this move at all. Our current CB crop aren't close to good enough. Hanson is most effective as a slot corner - he's not big or strong enough to play outside - but he's pretty good at what he does. At any rate, he's a short-term upgrade over most of what we have at the position.
Basically a low-risk move by Reggie to shore up our biggest need area on D.