An issue was discovered on Moxa AWK-3121 1.14 devices. The Moxa AWK 3121 provides certfile upload functionality so that an administrator can upload a certificate file used for connecting to the wireless network. However, the same functionality allows an attacker to execute commands on the device. The POST parameter "iw_privatePass" is susceptible to this injection. By crafting a packet that contains shell metacharacters, 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