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:I know it's Off Topic but

[xintegerx]

I'll try it right now. So instead of enter, I press F8?

hooray !

[maharg]

I have 2 Dell 6650s, loaded with 4 HT Xeons and 32Gb RAM each. However, I had to disable HT on them as the license for the application I'm running allows 8 cpus only; when it detected "16" cpus across the 2 servers, it refused to start. So this news actually makes me feel better about the fact that `top` only shows 4 cpus on each box :o)