When the program is infecting a new computer, it first checks an obscure web address — iuqerfsodp9ifjaposdfjhgosurijfaewrwergwea.com — to see if the domain is registered.

Backdooms is a compressed, self-extracting program encoded entirely within a single QR code. When scanned, it launches an infinitely generated HTML environment resembling Doom-style corridors ...