|There is a notable uptick in scanning for port 17185 that started early December 2013. I associate it with this later vulnerability announcement;
Siemens CP 1604 and CP1616 Communication Processor Debugger Interface Remote Access Vulnerability, http://tools.cisco.com/security/center/viewAlert.x?alertId=28721
CVSS Base 10.0
CVSS Temporal 7.4
"An unauthenticated, remote attacker could exploit this vulnerability by sending crafted packets to UDP port 17185 of a targeted system. Successful exploitation could allow the attacker to gain unauthorized access to the debugger interface of the system."