Cheaters Forcefully Infect Call of Duty Players’ Computers with Malware

Network security issues in older entries of the popular Call of Duty franchise have become something of a meme within the gaming community. The problem is absurd: ordinary cheaters, who are common in many online games, can not only annoy honest players thanks to Call of Duty’s flawed network code, but also infect their computers with real viruses. This goes far beyond just a ruined match or a spoiled evening.

Players of the original Call of Duty: Modern Warfare 2, released back in 2009, still enjoy revisiting the game from their childhood, often ignoring newer titles in the series. It’s these nostalgic multiplayer fans who are being targeted by malicious cheaters capable of spreading a worm virus directly in online lobbies before a match even loads.

On June 26, a user named “Bee” created a separate thread on the Steam forum to discuss this issue. “Make sure you have an antivirus scanner before launching this game. They’re attacking through hacked lobbies by replacing dsound.dll,” the player warned.

Another community member even analyzed the malware and posted in the same forum thread that it is a worm, based on several text strings found in the malicious code. Worms are known for their ability to self-replicate and automatically infect other computers.

New samples of this worm are regularly uploaded to VirusTotal. So far, only 4 out of 70 antivirus engines are able to detect it.

Yesterday, the official Call of Duty Twitter account announced that “the multiplayer for Call of Duty: Modern Warfare 2 (2009) on Steam has been taken offline while we investigate,” confirming the presence of a malware problem.

While the concept of spreading malware through video games isn’t new—usually happening via trojanized installers or pirated cheats from shady websites—it’s still unclear how attackers are able to forcibly infect other players’ computers directly through the game lobby.

This isn’t the first time hackers have manipulated the computers of regular Call of Duty players. The last such incident was reported in early March. Since these issues seem to only affect the Call of Duty series, many players have started to joke about the situation.

Call of Duty: Modern Warfare 2 was released by Activision in 2009, but still maintains a small, dedicated community. According to SteamDB, the game averages around 600 concurrent players at the time of this post.

Valve, the company behind the Steam platform where Call of Duty is distributed, has not commented on the situation. However, it’s unlikely they can do much more than temporarily remove the game from the store or block it from launching to protect players. The main responsibility lies with Activision, and as we know, fixing issues in old games isn’t something the controversial company is eager to spend time on.