In a month of security exploits and exposed flaws, a new bug in Intel’s Skylake and Kaby Lake processors has been exposed and it’s a serious one.
Contacting the Debian.org mailing list, Debian developer Henrique de Moraes Holschuh said that systems with hyperthreading enabled could "in some situations, dangerously misbehave". What this means is that "application and system misbehavior, data corruption, and data loss" are all real possibilities.
The two solutions highlighted by the devloper are to either update the processor microcode or, perhaps more simply, disable hyperthreading. The affected components are any Skylake or Kaby Lake processors that were released after September 2015.
As Hexus points out, Intel did add a note to its processors documentation a couple of months ago when it discovered these bugs, and officially gave the rather techy explaination of:
Under complex micro-architectural conditions, short loops of less than 64 instructions that use AH, BH, CH or DH registers as well as their corresponding wider register (eg RAX, EAX or AX for AH) may cause unpredictable system behaviour. This can only happen when both logical processors on the same physical processor are active.
What all of this means in real world terms is that owners of Intel’s 6th or 7th generation processors should turn off hyperthreading and wait for a UEFI/BIOS update from their motherboard vendor, or else they will run the risk of basically ruining their entire system. While this isn’t the kind of security flaw that can leave a system open to hackers, it is nonetheless a massive issue that Intel and its associated vendors would do well to adress quickly.
With AMD releasing its industry-shaking Ryzen CPUs over the past few months, the processor market it arguably at its most competitive point for the past several years. It would be presumptious to say that this would give AMD an upper hand in the market, but it can’t hurt.