Exploits
Usually included in this concept of cheating is the use of existing bugs or gameplay aspects unintended by the developers known as exploits. Gamers are divided as to whether all exploitation is cheating, though most consider exploits as cheats if they are particularly unfair. It is also difficult to classify some activities as exploits, because sometimes unintended features in games can make them much more fun to play, like bunny hopping in Quake. However, most exploits are unbalancing to a multiplayer game, and are called cheats because they are based on mistakes by the developers. For example, duping ruins a synthetic economy in online role-playing games and is rarely intended, and therefore is usually called a cheat.
External software
The most unbalancing cheats usually come from external software. Either the program that runs the game is modified to allow the player to cheat, or other software is run which produces the same results. Wallhacks, aimbots, and other cheats fall into this category.
Cheesing
Cheesing (occasionally referred to as "cheap") is not cheating per se; it refers to players in online multiplayer football games such as Madden NFL and NCAA making playcalls that wouldn't be made in real life, such as going for it on 4th down on their own 20. While doing this is within the rules unless players have formed a league and made an agreement not to cheese, it is generally frowned upon.
Disconnecting
In games where wins and losses are recorded on a players account, a player may disconnect from a game they have lost in order to prevent the loss from being recorded. A similar phenomenon is when someone running a server boots players who are beating them. Disconnecting can be accepted when there are multiple players in a game but if it is a one-on-one match it is considered immoral, as the opponent of the cheater will not have their "win" recorded.
Rigging
This kind of cheating often involves altering game settings or team lineups in order to give one team an unfair advantage over the other. One example includes filling a team with only skilled or known players and pitting them against another team of lesser skill. Though this tactic is not illegal, it often upsets lesser-skilled players who feel that they aren't being given a fair chance. Less ethical rigging involves giving one team more advantages such as better weapons or equipment. Riggers can also abuse games with map editors by creating maps that give the advantage to a certain team in the game.
Ranking up
Some games involve a global leader board, where each player is ranked according to how they have done in a game. It is entirely possible to cheat your way up to a high place through fake accounting, which is when someone creates an alternative account to let a person planning on raising his rank win without trying to beat him. These free wins help them reach the top of the leader board without having to compete against other players.
Sharing
The results of account sharing on the MMORPG Tibia (computer game).
Sharing is when multiple people share an online game (mainly MMORPG games) character. Common reasons for doing a sort of this is to gain a very unfair advantage by having higher online times, and being capable of having more manpower (for activities such as leveling or gaining experience). A common side effect from such cheating results in massive levels and/or massive loot.
Implementation of cheats
There are many facets of cheating in online games which make the creation of a system to stop cheating very difficult.
The game software
Many cheats in today's games are changes to the game software, although many game companies have policies which forbid the modification of such code. While the software (for most games) is distributed in binary-only versions and encrypted to make it harder, reverse engineering is always possible. Also many of the data files for the games can be edited without editing the main program and thereby circumvent protections in the software. Wallhacks and maphacks often function by modifying the software. Other cheats can analyze or change the game's state in RAM, such as some aimbots and programs that give infinite ammo or health (often called trainers).
The hardware
Turning up the brightness on the monitor or using specific graphic cards with drivers that allows you to look through walls ("wallhack") are examples of using hardware tricks to get an advantage. These are frequently impossible to track with software, but they also have limited effect.
Packet tampering
Some cheats completely circumvent the protection of the software by running in real-time and changing the game data while in transmission from the server to the client. Many aimbots, in first-person shooters use tricks like this. Some newer games encrypt the network data, but this uses up computer resources that could be used to make a faster-running or better game instead.
Preventing cheats
Game developers and third party software developers have created technologies that attempt to prevent players from cheating. Anti-cheating software is most commonly used in popular first person shooters such as Half-Life and its various mods or Quake. A few examples of anti-cheat software are PunkBuster, Cheating-Death, Valve Software's VAC ("Valve Anti-Cheat"), Argus Anti-Cheat, and RSVP First.
Some companies select to ban suspected cheaters from their servers. When this is done by blacklisting the game's serial key, the player is often effectively prevented from playing online the game they purchased.
It might not be financially wise for a company to fight "cheaters" in its games. Alternate characters are frequently banned in free games but they bring in revenue just like normal players in games that require subscription fees. Gamers have speculated that this is the reason why "two boxing" is not a bannable offense. Players are often less concerned about these circumstances because it might be debatable if the actions in question are a form of cheat.
It could be argued, however, that when a company does not take cheating seriously, they could very well be shortening the lifespan of their games. Some gamers have noted that recent games that have no serious anticheat are not high on their list of "games to purchase", while other games that do have some sort of anticheat system seem much more attractive. On the other hand, those that do cheat at these games might look at the situation the other way, and prefer games that have little to no anticheat system. Regardless of one's perspective, the stance a company takes on cheating could have a significant impact on whether one will decide to purchase a game or not. For this reason, a game company is left to consider the cost of working towards stopping cheating vs the cost of ignoring cheats.
