Re:Meltdown Proof-of-Concept
by warkdarrior on Tuesday January 09, 2018 @07:05PM
(#16111397)
Cache timing attacks have been known for a while, for example across VMs in 2009: https://cseweb.ucsd.edu/~hovav/dist/cloudsec.pdf
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This paper from 2005 describes a cache timing attack that enabled an unprivileged process to another process' AES key:
https://www.cs.tau.ac.il/~tromer/papers/cache.pdf
IIRC, the only way to address the issue was the addition of the AES-NI instruction set, which came a few years later.
> IIRC, the only way to address the issue was the addition of the AES-NI instruction set, which came a few years later.
Another option would be to use a bitsliced implementation of AES, at some cost in speed. I could also imagine an implementation which read the whole table every time, using constant-time operations to select the desired element(s), but I don't know how slow that would be.