Call of Duty adds Server Culling to block wallhacks

Infinity Ward will deploy a Server Culling system in Modern Warfare 4 that withholds player location data when opponents are occluded. The feature will be active on every map at launch, including DMZ and Combat Outpost, and will extend to new multiplayer, DMZ and Warzone maps in Season 1 and beyond.

Wallhacks read location data the multiplayer server sends to each game client so players can see opponents without a direct line of sight. Server Culling uses map-specific occlusion layers placed inside buildings and objects to let the server determine when two players have no legitimate way to see one another. When the server judges a player fully occluded, it withholds that player’s location from the other client until they move back into view.

Team Ricochet, the franchise’s anti-cheat group, is implementing Server Culling. The group previously used systems called Quicksand, which interfered with cheaters’ controls, and Hallucinations, which presented phantom players visible only to hackers. The occlusion-based method adapts a common game-development technique to remove visibility data that cheats exploit.

A developer on the project commented, “Few things ruin a great match faster than an opponent who can see you through a wall.” The studio wrote, “Cheat software can’t reveal information it never receives.” Infinity Ward confirmed that “Server Culling will cover every map available at launch for Modern Warfare 4,” and that the team will continue to strengthen the layer technology.

Modern Warfare 4 ships Friday, October 23, giving the studio an opportunity to test Server Culling at scale. The studio plans updates as new maps and seasons arrive.

Server-side filtering of visibility data targets the specific vulnerability wallhacks use, while other anti-cheat measures focus on detecting and penalizing unauthorised software. Whether reports of cheating decline will become clearer after launch and during the first live season.