Shodan

Overview
Shodan is

{{Quote|an Internet search engine that sought to identify devices that are linked to the Internet. Users of the search engine discovered that many devices were connected to the Internet unintentionally and usually with minimal security provisions. Notably, users discovered that many ICS devices, such as pump controllers at municipal water plants and utility SCADA networks, were connected to the Internet unbeknownst to the operator. Additionally, many of these devices have little or no security; typically no more than a simple factory-set password that the user usually does not change. The danger exposed by Shodan is that ICS devices, which have relied on security by obscurity, are becoming known and controllable through their interaction with the Internet, even when the user is unaware that the device is connected to the Internet.