This indicates an attack attempt to exploit a Remote Command Execution vulnerability in Western Digital My Book Live.
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.
Western Digital My Book Live
Western Digital MyCloud NAS
System Compromise: Remote attackers can gain control of vulnerable systems.
Currently we are unaware of any vendor supplied patch for this issue.