Hackers

Also, can hackers sniff out your password and pin without installing a keylogger on your computer?

They would have to utilize some form of social engineering (Impersonation a Zak helm selling group, various forms of phising) to get that info otherwise.

The only time where I think someone could have gotten that info without keyloggers or social engineering is when hackers were able to exploit something on the MapleSEA ranking pages to get account information, but I don't think anyone has tried to do that for Global MS yet, let alone that we don't know if the Global MS rankings can be exploited in the same matter as SEA's.