The purpose was to steal PIN codes and hijack MSC's containers.
An article at Bloomberg relates the story of two IT professionals who reluctantly teamed up with an organized criminal network in building a sophisticated drug smuggling operation. "[The criminals were] clever, recruiting Van De Moere and Maertens the way a spymaster develops a double agent. By the time they understood what they were involved in, they were already implicated." The pair were threatened, and afraid to go to the police. They were asked to help with deploying malware and building "pwnies" — small computers capable of intercepting network traffic that could be disguised as power strips and routers.