VIA C3 procesori kompromitirani jednostavnom naredbom ljuske



VIA processors probably make up an infinitesimal amount of the desktop PC market-share, and its makers market the chip only at pre-built machines such as digital-signage kiosks, information kiosks, ticket vending machines, ATMs, etc (which don't need a lot of processing power). At the Black Hat 2018 conference, security researcher Christopher Domas discovered that getting access to root privileges in Linux on a machine powered by VIA C3 'Nehemiah' processors is laughably easy. Just key in '.byte 0x0f, 0x3f' (without quotes) in any Linux CLI in user mode, and voila! You are now the root user.

Domas ovo naziva svojim iddqd (cheat-code za 'God Mode' u 'Doom'). Ova stražnja vrata, koju su vjerojatno postavili sami dizajneri procesora, u potpunosti srušuje prstenski privilegirani operativni sustav i uzbunjuje korisnike i programe s ring-2 (i iznad) korisničkog prostora na zvono 0 (root). To je iskorištavanje jezgre sjene, skrivenog RISC procesora unutar C7, koji upravlja pokretanjem, radom i pohranom ključa x86 jezgara. Intel i AMD također imaju jezgre sjene sa sličnim funkcijama.
Source: Tom's Hardware