The following account in Matthew should give all an idea of the enemy's current allowance of authority.
Mat 4:8 Again, the devil taketh him up into an exceeding high mountain, and sheweth him all the kingdoms of the world, and the glory of them;
Mat 4:9 And saith unto him, All these things will I give thee, if thou wilt fall down and worship me.
Having shared this, I have read, where I do not recall, that Satan has power to the third heaven. Since I have no list of levels of heaven in my H=heart, I suffice it for myself that his power is at least in this age here for deception and worse, therefore I rely on the gift of faith and the protection afforded us allby faith.