Cisco IP Phone (VoIP) 7920 1.0(8) listens to UDP port 17185 to support a VxWorks debugger, which allows remote attackers to obtain sensitive information and cause a denial of service.
https://exchange.xforce.ibmcloud.com/vulnerabilities/23068
http://www.securityfocus.com/bid/15456
http://www.cisco.com/warp/public/707/cisco-sa-20051116-7920.shtml