The Assets subsystem in Apple iOS before 8 and Apple TV before 7 allows man-in-the-middle attackers to spoof a device's update status via a crafted Last-Modified HTTP response header.
http://archives.neohapsis.com/archives/bugtraq/2014-09/0106.html
http://archives.neohapsis.com/archives/bugtraq/2014-09/0107.html
http://support.apple.com/kb/HT6441
http://support.apple.com/kb/HT6442
http://www.securityfocus.com/bid/69882
http://www.securityfocus.com/bid/69941