Bugs and flaws in software are the cause for a majority of computer security problems. This was true for online banking and now it is true for online gaming, too. Software contains so many security-related bugs and software vendors have also developed special tools that just perform a job of finding bugs but these tools are not very effective. These tools did help a bit but also complicated the situation and the experts have produced thousand of papers on bugs' taxonomy but unfortunately, most of them disagree with each other.
One of the most common security bugs involves time and state problems. This problem arises because of the necessity of the system state to be shared among many distributed processors - all having different levels of trustworthiness. If we take an example of a famous online game - World of Warcraft, we see that it too has to share game's state information with tons of client programs at the same time and when all the clients' processes interlink on a single server in real time, the state confusion attacks popup. And when the state information of a game is cracked off and sent to the untrusted game clients, this causes the most serious problems.
Another common attack associated with state is often called telehacking. It is related to traveling of the game characters e.g. walking, flying, running, teleporting, etc. The manipulation of a character state is usually done in the client software. Many online games exploits modify the mechanism how a client program handles the character's travel. A cheating gamer finds and changes or resets the player's character's coordinates by manipulating the state and the location parameters in the memory. Even overwriting a single byte in a game such as World of Warcraft can make a character to climb mountains, climb straight walls, etc. This method is common among game hackers, they do it to get into some places where they are not supposed to get into. Because most online games seem very real, if a game cheater moves any character a little from its current location, this action can appear to be normal.