The Mobile and Remote Access (MRA) endpoint-validation feature in Cisco TelePresence Video Communication Server (VCS) Expressway X8.5.2 improperly validates the phone line used for registration, which allows remote authenticated users to conduct impersonation attacks via a crafted registration, aka Bug ID CSCuv40396.
http://www.securitytracker.com/id/1033282
http://www.securityfocus.com/bid/76353
http://tools.cisco.com/security/center/viewAlert.x?alertId=40445