Valve Anti-Cheat
Encyclopedia
Valve Anti-Cheat, abbreviated to VAC, is an anti-cheat solution developed by Valve Corporation
as a component of the Steam game development platform.
1.4 in 2002, following Valve's decision to forego PunkBuster
in preference of a proprietary system. The initial version, VAC1, saw success for a period, but in March or April 2004 updates ran dry as the Valve engineers maintaining it moved on to the production of its successor, VAC2.
Valve does not normally discuss VAC, and very little is known about its internal workings. However, on November 17, 2006 they announced that "new [VAC] technology" had caught "over 10,000" cheating attempts in the preceding week alone, the first real indication of the scale of anti-cheat operations. Not all of the accounts banned would have contained legitimate, purchased games, and there is no external audit on the figure.
As of 2010, unofficial sources estimate that over a million Steam accounts have been banned by VAC.
games, Unreal engine
games). Valve never discloses which cheat was detected.
.
Cheats may be hidden inside otherwise legitimate mod or skin downloads that are created to maliciously get innocent people banned. Since the source of a cheat installed on a computer cannot be proven, bans due to this are never rescinded.
Valve has "a zero-tolerance policy for cheating and will not lift VAC bans under any circumstances." This includes account hijacking and other circumstances beyond the control of the account's owner.
item called the Golden Wrench found themselves banned by VAC.
Valve Corporation
Valve Corporation is an American video game development and digital distribution company based in Bellevue, Washington, United States...
as a component of the Steam game development platform.
History
VAC was first released with Counter-StrikeCounter-Strike
Counter-Strike is a tactical first-person shooter video game developed by Valve Corporation which originated from a Half-Life modification by Minh "Gooseman" Le and Jess "Cliffe" Cliffe...
1.4 in 2002, following Valve's decision to forego PunkBuster
PunkBuster
PunkBuster is a computer program that is designed to detect software used for cheating in online games. It does this by scanning the memory contents of the local machine. A computer identified as using cheats may be banned from connecting to protected servers. The aim of the program is to isolate...
in preference of a proprietary system. The initial version, VAC1, saw success for a period, but in March or April 2004 updates ran dry as the Valve engineers maintaining it moved on to the production of its successor, VAC2.
Valve does not normally discuss VAC, and very little is known about its internal workings. However, on November 17, 2006 they announced that "new [VAC] technology" had caught "over 10,000" cheating attempts in the preceding week alone, the first real indication of the scale of anti-cheat operations. Not all of the accounts banned would have contained legitimate, purchased games, and there is no external audit on the figure.
As of 2010, unofficial sources estimate that over a million Steam accounts have been banned by VAC.
Advantages
- Total integration through Steam, including using the Steam framework for any update tasks
- Delayed bans deny cheat producers accurate and timely information. This causes a reduction in the supply of cheat programs to players who want to cheat online.
Disadvantages
- VAC cannot detect 'content hacks', where, for example, texture transparency and color are manipulated, since they do not involve modifing any program code. In the Source the option to create "pure" servers (
sv_pure) that prevent custom content from overwriting the game's defaults was created to alleviate this.
Delayed bans, criticism & rationale
If a cheat is found the player's Steam account will be flagged as cheating immediately, but the player will not receive any indication of the detection. It is only after a delay of "days or even weeks" that the account is permanently banned from "VAC Secure" servers for that game, along with other games that use the same engine. (e.g. Valve's Source games, GoldSrcGoldSrc
GoldSrc, or Goldsource, is the retronym used internally by Valve Software to refer to the heavily modified Quake engine that powers their science fiction first-person shooter Half-Life ....
games, Unreal engine
Unreal Engine
The Unreal Engine is a game engine developed by Epic Games, first illustrated in the 1998 first-person shooter game Unreal. Although primarily developed for first-person shooters, it has been successfully used in a variety of other genres, including stealth, MMORPGs and RPGs...
games). Valve never discloses which cheat was detected.
False-positive detections
There have been allegations that VAC has banned users for false positivesType I and type II errors
In statistical test theory the notion of statistical error is an integral part of hypothesis testing. The test requires an unambiguous statement of a null hypothesis, which usually corresponds to a default "state of nature", for example "this person is healthy", "this accused is not guilty" or...
.
- There are six recorded instances of incorrect detections, which were fixed and rescinded:
- VAC1: On its initial release, VAC would issue bans for faulty memoryRandom-access memoryRandom access memory is a form of computer data storage. Today, it takes the form of integrated circuits that allow stored data to be accessed in any order with a worst case performance of constant time. Strictly speaking, modern types of DRAM are therefore not random access, as data is read in...
. Valve quickly updated VAC to only kick for faulty memory. - VAC1: Running a VAC-protected game through the Cedega software compatibility layer for Linux.
- VAC1: An apparent server-side glitch on April 1, 2004.
- VAC2: Over two weeks in July 2010, approximately 12,000 owners of Call of Duty: Modern Warfare 2Call of Duty: Modern Warfare 2Call of Duty: Modern Warfare 2 is a first-person shooter video game developed by Infinity Ward and published by Activision for the Xbox 360 and PlayStation 3 video game consoles and the Microsoft Windows operating system. Officially announced on February 11, 2009, the game was released worldwide on...
were banned when Steam updated a DLLDynamic-link libraryDynamic-link library , or DLL, is Microsoft's implementation of the shared library concept in the Microsoft Windows and OS/2 operating systems...
file on-disk after it had been loaded into memory by the game. Those affected received a free copy of Left 4 Dead 2Left 4 Dead 2Left 4 Dead 2 is a cooperative first-person shooter video game. It is the sequel to Valve Corporation's award-winning Left 4 Dead. The game launched on November 17, 2009, for Microsoft Windows and Xbox 360 in the United States and November 20 in Europe; in 2010, Left 4 Dead 2 was made available to...
or an extra copy to send as a gift. - VAC2: In January 2011, owners of Call of Duty: Modern Warfare 2Call of Duty: Modern Warfare 2Call of Duty: Modern Warfare 2 is a first-person shooter video game developed by Infinity Ward and published by Activision for the Xbox 360 and PlayStation 3 video game consoles and the Microsoft Windows operating system. Officially announced on February 11, 2009, the game was released worldwide on...
or Call of Duty: Black OpsCall of Duty: Black OpsCall of Duty: Black Ops is a first-person shooter video game developed by Treyarch, published by Activision and released worldwide on November 9, for Microsoft Windows, Xbox 360, PlayStation 3, Wii consoles, with a separate version for Nintendo DS developed by n-Space. Announced on April 30, 2010,...
were banned due to their computers being infected by the trojanTrojan horse (computing)A Trojan horse, or Trojan, is software that appears to perform a desirable function for the user prior to run or install, but steals information or harms the system. The term is derived from the Trojan Horse story in Greek mythology.-Malware:A destructive program that masquerades as a benign...
Win32/Spyeye.H. - VAC2: In June 2011, an unknown false positive detection caused a handful of Team Fortress 2Team Fortress 2Team Fortress 2 is a free-to-play team-based first-person shooter multiplayer video game developed by Valve Corporation. A sequel to the original mod Team Fortress based on the Quake engine, it was first released as part of the video game compilation The Orange Box on October 10, 2007 for Windows...
owners to become banned.
- VAC1: On its initial release, VAC would issue bans for faulty memory
- There are four recorded instances of game plugins that are not considered cheats triggering bans. These are:
- VAC1: HLamp, which allowed the user to control WinampWinampWinamp is a media player for Windows-based PCs and Android devices, written by Nullsoft, now a subsidiary of AOL. It is proprietary freeware/shareware, multi-format, extensible with plug-ins and skins, and is noted for its graphical sound visualization, playlist, and media library features.Winamp...
from the game's interface. Detection later reversed, and all bans caused by it rescinded. - VAC2: The X-Spectate tool, which allowed server administrators to enable a wallhack effect while spectating to help decide if another player was doing the same. Later downgraded to a kick from the server, but bans not rescinded.
- VAC2: The single-player Half-Life modifications Paranoia and Half-Life FX, which made changes to the engine's rendererRendering (computer graphics)Rendering is the process of generating an image from a model , by means of computer programs. A scene file contains objects in a strictly defined language or data structure; it would contain geometry, viewpoint, texture, lighting, and shading information as a description of the virtual scene...
that propagated to multiplayer games. This still triggers a ban and no bans caused by it have been reversed. - VAC and VAC2: sXe Injected, an anti-cheat system for Counter-StrikeCounter-StrikeCounter-Strike is a tactical first-person shooter video game developed by Valve Corporation which originated from a Half-Life modification by Minh "Gooseman" Le and Jess "Cliffe" Cliffe...
.
- VAC1: HLamp, which allowed the user to control Winamp
Cheats may be hidden inside otherwise legitimate mod or skin downloads that are created to maliciously get innocent people banned. Since the source of a cheat installed on a computer cannot be proven, bans due to this are never rescinded.
Valve has "a zero-tolerance policy for cheating and will not lift VAC bans under any circumstances." This includes account hijacking and other circumstances beyond the control of the account's owner.
Manually applied bans
In July 2010, several players who successfully used information leaked from Valve to increase their chances of finding a special Team Fortress 2Team Fortress 2
Team Fortress 2 is a free-to-play team-based first-person shooter multiplayer video game developed by Valve Corporation. A sequel to the original mod Team Fortress based on the Quake engine, it was first released as part of the video game compilation The Orange Box on October 10, 2007 for Windows...
item called the Golden Wrench found themselves banned by VAC.
Games that support VAC
Mods based on the games above may inherit VAC support from the host game.See also
- Cheating in online gamesCheating in online gamesCheating in online games is an activity that modifies the game experience to give one player an advantage over others. Depending on the game, different activities constitute cheating and it is either a matter of game policy or consensus opinion as to whether a particular activity is considered to...
- PunkBusterPunkBusterPunkBuster is a computer program that is designed to detect software used for cheating in online games. It does this by scanning the memory contents of the local machine. A computer identified as using cheats may be banned from connecting to protected servers. The aim of the program is to isolate...
- Steam (software)
- Warden (software)