Counter-Strike: Global Offensive players will no longer be able to resell or trade their container keys between their accounts because Valve has discovered that their trade is part of a global fraud network. Players could earn containers with weapons and other in-game items but had to purchase keys in order to open them, with key and container trading possible through Valve’s Steam marketplace. A patch released this week on October 28th removes the ability to exchange these items, with a post on Counter-Strike‘s official blog explaining the problem.

“In the past, most key trades we observed were between legitimate customers. However, worldwide fraud networks have recently shifted to using CS:GO keys to liquid their gains. At this point, nearly all key purchases that end up being traded or sold on the marketplace are believed to be fraud-sourced,” the official blog post reads.

Previously purchased container keys can still be sold or traded on the Steam Community Market, but keys purchased after the patch cannot. “Unfortunately this change will impact some legitimate users, but combating fraud is something we continue to prioritize across Steam and our products,” the post from Valve and Counter-Strike reads. Buying and using keys and containers for your own account will work the same way and is not being changed.

Valve previously adjusted how trading works in Counter-Strike: Global Offensive in 2018, adding a seven-day cooldown on trading that placed holds on any transactions that “use automated Steam accounts to mimic players and make sure of Steam’s trading functionality” for fraud purposes as a way to prevent third-party services from exploiting the trade features.

Counter-Strike: Global Offensive has seen its share of legal concerns. This year the Native American Quinault Tribal Nation filed suit against Valve in Washington state, alleging that Valve participates in “unethical, oppressive, and unscrupulous business conduct” by facilitating illegal online gambling for CS:GO skins and illegally competing with the Quinault Beach Resort and Casino, which is legally licensed and regulated. Another case involving YouTubers Trevor ‘TmarTn” Martin and Thomas “Syndicate” Cassell culminated in an order from the Federal Trade Commission ordering that all influences disclose any ties with anything promoted in their videos after the two were found to be promoting a skin gambling website that they owned.

In January of this year reports emerged that V-Bucks, the currency used in Fortnite, were also being used as a way to launder money. Stolen credit card information was allegedly being used to purchase “large quantities of V-Bucks through the in-game store. They are then taking their haul and selling insane quantities of V-Bucks on the dark web (through the nearly untraceable bitcoin) and through more visible channels to a lesser extent.”