Oopsie: Publisher Bethesda apparently made a big boo-boo with its recent launch of Doom Eternal. As users on Reddit and ResetEra quickly discovered, the publisher "accidentally" left a DRM-free copy of the game's executable in the download package.
It was confirmed earlier this week once the review embargo lifted that Doom Eternal would use anti-tamper technology Denuvo to help slow piracy out of the gate. Once users had a chance to poke around the game files, however, they discovered a DRM-free executable sitting right there in plain sight - in a folder labeled "original," nonetheless.
According to this Reddit user, the primary executable weighed in at 369 MB and could be found in the main game folder. In the subfolder, there was a smaller 67 MB executable that could easily be copied to the main folder to overwrite the Denuvo executable.
From there, all you had to do was launch the game, create a Bethesda account (this appears to be a mandatory step although according to Ars Technica, crackers have already discovered a workaround to enable a fully offline experience) and start playing.
As you've likely guessed, Bethesda was quick to issue a patch that removed the DRM-free executable but the damage has already been done and the publisher has nobody to blame but itself for seeding a DRM-free version of Doom Eternal.
This isn't the first time such a thing has happened, either. Bethesda experienced a similar slip up last year with Rage 2 and ultimately removed Denuvo from the Steam version days later.