Hyperthreading Considered Harmful

cperciva writes "Hyper-Threading, as currently implemented on Intel Pentium Extreme Edition, Pentium 4, Mobile Pentium 4, and Xeon processors, suffers from a serious security flaw. This flaw permits local information disclosure, including allowing an unprivileged user to steal an RSA private key being used on the same machine. Administrators of multi-user systems are strongly advised to take action to disable Hyper-Threading immediately. I will be presenting this attack at BSDCan 2005 at 10:00 AM EDT on May 13th, and at the conclusion of my talk I will also releasing a paper describing the attack and possible mitigation strategies."

Comments

Re:Is this a hyperthreading problem or..

[Jondaley]

I haven't seen the attraction of hyperthreading. My father said that it is great because now he can read his email (at work) while running his compiler, rather than the compiler taking up all of the CPU.

I said he should just lower the process priority of his compiler (or raise it on his email client).
Then, the compiler can use 100% of the CPU when he isn't surfing the web on company time...

I got a machine that has it, and I turned it off in the BIOS. I have been meaning to do some comparisons, to see if I can notice.

So does anyone know...

[http101]

...if this affects AMD processors with Hyper Transport technology? I'm curious since AMD's Hyper Transport is similar to Intel's Hyper Threading, but in my books, superior.

Re:Paper

[owlstead]

Mod parent up?