My friend was hacked while logged in

[Namasu]

And dozens of people did the same thing in the last few hours?

I don't know what you mean by that. Dozens and dozens and dozens of people were also hacked the first month because they have terrible password management (ex. using same login combination for different game like LoL led to many players getting hacked).

Also, if somehow a group of RMT hackers were to obtain a large pool of FFXIV player's IP (from 3rd party gaming forums etc.), I wouldn't dismiss the possibilities of them taking advantage of the less computer savy player with little knowledge of computer security and scan for vulnerable ports to gain full remote access.

Sure there could be an exploit in game that let someone use my character as a puppet and steal my gil through the market place but I don't see enough evidence to prove that it's totally an in-game security issue and not the case that I brought up above.