An exploitable local privilege elevation vulnerability exists in the file system permissions of Moxa MXView series 3.1.8 installation. Depending on the vector chosen, an attacker can either add code to a script or replace a binary. By default MXViewService, which starts as a NT SYSTEM authority user executes a series of Node.Js scripts to start additional application functionality.
During installation, installed file permissions are set to allow anyone to modify those files.
- Compartmentalize the system to have “safe” areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
- Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.