3,200 Sollae Systems (Serial-Ethernet-Module/Remote-I/O-Device-Server etc.) Telnet-Service had Exposed on the internet : https://www.zoomeye.org/searchResult?q=%22Sollae%20Systems%22%20%2Bport:%2223%22&t=all There are 1,300 in 2018,Almost in Korea. Most devices do not require password authentication Or use the default password: sollae 
3,200 Sollae Systems (Serial-Ethernet-Module/Remote-I/O-Device-Server etc.) Telnet-Service had Exposed on the internet : https://www.zoomeye.org/searchResult?q=%22Sollae%20Systems%22%20%2Bport:%2223%22&t=all There are 1,300 in 2018,Almost in Korea. Most devices do not require password authentication Or use the default password: sollae 