The remote-support feature on Cisco Web Security Virtual Appliance (WSAv), Email Security Virtual Appliance (ESAv), and Security Management Virtual Appliance (SMAv) devices before 2015-06-25 uses the same default SSH host keys across different customers' installations, which makes it easier for remote attackers to defeat cryptographic protection mechanisms by leveraging knowledge of a private key from another installation, aka Bug IDs CSCus29681, CSCuu95676, and CSCuu96601.
http://www.securitytracker.com/id/1032726
http://www.securitytracker.com/id/1032725
http://www.securityfocus.com/bid/75418
http://tools.cisco.com/security/center/viewAlert.x?alertId=39461
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20150625-ironport