Valve to implement security improvements for Steam devs accounts after attacks of games updated with malware
Some reports mention that less than 100 Steam accounts were affected, and according to some of the emails sent out to the users (which date back to Septermber, 2023), the compromised game builds (for some cases) were updated on August 24th, 2023, and then reverted back on August 25th, 2023. The game mentioned in the Twitter/X post above has been confirmed to be NanoWar: Cells VS Virus developed by Benoît Freslon, who had all of his accounts compromised due to the attack, but at the time of writing, it is yet to be confirmed which other games specifically have been affected by this malware attack, and if the compromised builds were all updated on the same dates listed in the mail or if it was a case-per-case basis for the malware-infected game builds.
As a response to these hacks, Valve has started to take action, and to counter these malware attacks, and improve the security of their developers, Steam will be implementing new changes to manage builds and Steamworks users, in which they are now requiring the Steamworks accounts to have a phone number associated with their account to get an SMS confirmation through the mobile device; basically Two-Factor Authentication/2FA but for certain changes instead of a login, and this will be effective for both managing builds of games as well as adding new users too.
Valve's Developer Event post said:We wanted to give everyone a heads up on some important changes to how builds will be managed in Steamworks, along with adding new users to your Steamworks partner. As part of a security update, any Steamworks account setting builds live on the default/public branch of a released app will need to have a phone number associated with their account, so that Steam can text you a confirmation code before continuing. The same will be true for any Steamworks account that needs to add new users. This change will go live on October 24, 2023, so be sure to add a phone number to your account now. We also plan on adding this requirement for other Steamworks actions in the future.
As mentioned in the excerpt from Valve, the change will take effect on October 24th, 2023, and Valve is considering implementing said changes for other Steamworks actions later down the road. Some Steam developers haven't been to keen to these kind of changes, but if it means more security for everyone, end-user or developer, it's a necessary change for the better.
Source
Valve's Developer Event Post