CSGO and Team Fortress 2 source code leaks with big implications

By Nick Johnson


Apr 22, 2020

Reading time: 3 min

The source code for Counter-Strike: Global Offensive and Team Fortress 2 has been leaked online, posing a huge issue for Valve and the communities of both games.

Valve News Network’s Tyler McvVickers was originally blamed for the leak by 4chan, but McVicker is adamant that he did not leak the code, but he knows who did. On a Q&A Twitch stream, McVicker explained that the code was provided to him by a source, but he was unable to verify that it was legitimate. He goes on to say that he had shared it with several people, excited that the leak might have been his first real source inside Valve. The curator of Valve News Network says that all information he had surrounding the events has been passed to Valve.

Interestingly, the actual source code released isn’t actually a new leak. It was originally released online in late 2018 by “a member of the Source Engine development community,” according to McVicker. Chat logs between McVicker and a someone he says claiming Valve employee were included with the files.

He says the logs were predated the code by more than a year, but were shared between himself and his close friends who routinely discuss the software developer and what they could be doing behind the scenes. The Valve News Network host claims that he never had access to any of the code, although he admits that the release of the chat logs alongside the source code doesn’t paint him in a good light.

Counter-Strike’s popularity makes a source code leak a much bigger deal

In 2018, during the original release of the code, Counter-Strike: Global Offensive had hit a rough patch. Valve was hard at work on Half-Life: Alyx and had just released Danger Zone’s second map, Jungle, and a remake of the classic map Inferno for CSGO. While Danger Zone drew some back into Valve’s first person shooter, it’s player counts were still low enough that a source code leak could be easily contained. Now, just after Counter-Strike broke Dota 2’s record for most concurrent players, a leak is much harder to control.

A picture of the source code file structure from SteamDB

What players have on their computer isn’t the source code to either CSGO or Team Fortress 2. Instead, the source code is complied into a file at release that looks nothing like the code itself. Trying to turn game files back into source code is like trying to turn scrambled eggs back into regular eggs – it just isn’t possible.

The danger from public source code is that once in the hands of programmers, cheat developers, and hackers, the code is dissected and studied. Through this process, those with the technical know-how can devise ways to exploit vulnerabilities in the code to create hacks, crash servers, and even hack computers running the games.

So far, one Team Fortress 2 community has already shut down in response to the leak. 

It’s an unfortunate development for both games. The leaked code has the potential to result in an increased presence of cheats in both games, something McVicker says has already happened as a result of the code’s initial leak, Luckily for CSGO, the difference between the game’s code in 2018 and now is large. With the UI’s almost complete move to Panorama, as well as the rumored move to Source 2, odds are that anyone with ill intentions will focus on Team Fortress 2. Players beware.


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