ASCEND: A search engine for online industrial control devices

Industrial control system (ICS) devices with IP addresses are accessible on the Internet and play a crucial role for critical infrastructures like power grid. However, there is a lack of deep understanding on these devices' characteristics in the cyber space. In this paper, we propose ASCEND, a search engine for online industrial control devices. ASCEND analyse 17 industrial protocols and use it to discover almost all online ICS devices in the IPv4 while reducing the noise of industrial honeypots. It provides a big picture of online ICS devices: who are using ICS devices; where they are located and what functions these ICS device have. In order to demonstrate how ASCEND works, we have implemented the prototype system and verified it in the real-world experiments.