Microhard Systems 3G/4G Cellular Ethernet and Serial Gateway systems have a web shell application that includes a service called Microhard Sh that is documented only as ‘reserved for internal use’. This service can be enabled by an authenticated user within the Services menu in the web admin panel. This can also be enabled via CSRF attack. When the service is enabled, a user ‘msshc’ is created on the system with password ‘msshc’ for SSH shell access on port 22. When connected, the user is dropped into a NcFTP jailed environment, that has limited commands for file transfer administration. One of the commands is a custom added ‘ping’ command that has a command injection vulnerability that allows the attacker to escape the restricted environment and enter into a root shell terminal that can execute commands as the root user. Many versions are affected.