This indicates an attack attempt to exploit a Command Injection vulnerability in Mitsubishi Electric ME-RTU devices.
The vulnerability is due to insufficient sanitizing of user supplied inputs. A remote attacker may be able to exploit this to execute arbitrary commands within the context of the application, via a crafted HTTP request.
Mitsubishi Electric ME-RTU devices through 2.02 and INEA ME-RTU devices through 3.0
System Compromise: Remote attackers can gain control of vulnerable systems.
Currently we are unaware of any vendor supplied patch for this issue.