Nexons Notice to Tyrant Gear

Good luck effectively, and cost efficiently, protecting your game against packet hacks.

Huh?
It's really very simple: validate every packet you receive.
Yes, it means checking every field has a legal value. A sequence of trivial "if"s that any beginning programmer can do.
What's this "effectively and cost efficiently"? It's bloody essential to do it. They know hackers have packet editors, they know that these hackers will attempt to distort any packet, especially those that contain a reward item ID, for their own purposes.
But they keep leaving themselves wide open to exploits that are essentially identical to previous ones.
Is cleaning up after an exploit really more effective and cost efficient than preventing it in the first place?