Silver Fox's identity is rather open at the moment. Originally, Wolverine and Sabretooth remembered Creed killing her decades ago. She returned, alive and well, in Wolverine (2nd series) #49 as a Hydra section chief, pointing out her death as a false memory implant. She died again in #64 at Creed's claws.
However, after Logan regained his full true memories after House of M, it seems she really did die back in the cabin. This opened the possibility that the Hydra Fox was a doppelganger, perhaps with memory implants of her own to make her believe she was Silver Fox.
Recently, though, Marvel's Voices: Indigenous Voices #1 reported Silver Fox was a mutant with healing powers. Now, the possiblity remained that Silver Fox survived and healed from the attack in the cabin somehow, and in fact was the Hydra operative as she appeared.