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Retbleed: Your x86 Speculative Attack Du Jour

RetbloodToday Intel released two security advisories addressing 2 medium severity vulnerabilities reported by academic researchers from ETH Zurich who have labeled their side-channel attack as “Retbleed” due to finding  a method to potentially bypass a commonly used mitigation technique known as retpoline.”

That’s what Intel said on their blog but the Ars Technica article sure makes this sound more serious than “medium”.  According to Ars Technica:

Retbleed can leak kernel memory from Intel CPUs at about 219 bytes per second and with 98 percent accuracy. The exploit can extract kernel memory from AMD CPUs with a bandwidth of 3.9 kB per second. The researchers said that it’s capable of locating and leaking a Linux computer’s root password hash from physical memory in about 28 minutes when running the Intel CPUs and in about 6 minutes for AMD CPUs.

So if I can run code on an x86 server and recover the root password in less than half an hour…that is not medium.

And fixing this could cost up to a 28% performance overhead.  Ouch.

Patch up!

There is a white paper available.  Unfortunately, no cool logo yet.


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