Cisco Adaptive Security Appliances (ASA) 5500 series devices with software 8.2 through 8.4 process IKE requests despite a vpnclient mode configuration, which allows remote attackers to obtain potentially sensitive information by reading IKE responder traffic, aka Bug ID CSCtt07749.
http://www.securitytracker.com/id?1027008
http://www.cisco.com/web/software/280775065/45357/ASA-825-Interim-Release-Notes.html