An issue was discovered on Moxa AWK-3121 1.14 devices. It provides ping functionality so that an administrator can execute ICMP calls to check if the network is working correctly. However, the same functionality allows an attacker to execute commands on the device. The POST parameter "srvName" is susceptible to a buffer overflow. By crafting a packet that contains a string of 516 characters, it is possible for an attacker to execute the attack.
https://seclists.org/bugtraq/2019/Jun/8
https://github.com/samuelhuntley/Moxa_AWK_1121/blob/master/Moxa_AWK_1121