Can other players crash my game?

I have already heard that a friend of mine has done this in Minecraft many times, but now I was threatened in GTA and my game crashed. How do they do it? And what can you do about it?

By changing the values of certain characters or items

e.g. A character has the values

32 01 - ultimate attack

24 01 = normal attack

etc

then you only have to change one of the values to either increase these powers or to ensure that the game crashes