An issue was discovered on Moxa AWK-3121 1.14 devices. The device by default allows HTTP traffic thus providing an insecure communication mechanism for a user connecting to the web server. This allows an attacker to sniff the traffic easily and allows an attacker to compromise sensitive data such as credentials.
https://seclists.org/bugtraq/2019/Jun/8
https://github.com/samuelhuntley/Moxa_AWK_1121/blob/master/Moxa_AWK_1121