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It seems the HN title and original title are both pretty wrong, at least according to the article content. The attack vector is really the ability to, if you ha
by andrewstuart2 10y ago
It seems the HN title and original title are both pretty wrong, at least according to the article content. The attack vector is really the ability to, if you have a known public key and a server using it, perform a pre-calculated bit flip such that the new public key is much easier to factor, and thus obtain a corresponding private key.
So you're not obtaining original private keys, you're altering original public keys so that you can more quickly factor a private key that will be accepted.
If this is an SSH public key, then you can obtain SSH access. If it's a PGP key trusted by the package manager, then you can craft signatures on packages that would be accepted as valid, assuming you can also get the target machine to download said package.
I think SSH is probably the most interesting attack vector assuming you can get network access to the host once you've jumped through the myriad hoops to perform this attack.
It's a serious issue that should be addressed (probably via forced from-disk reads or at minimum integrity checks), but I think the authors are perhaps a little too eager on the practical implications of corrupting in-memory public keys.
- DigitalJack 10y agoIt's the sort of thing for which the NSA would spend their resources to develop an exploit tool.
- userbinator 10y agoRowhammer is such a subtle effect and very easily blamed on many other things that it's not hard for the more paranoid among us to imagine the NSA deliberately sabotaging memories with it to use as a backdoor. When it was first discovered I wrote my thoughts on it here: https://news.ycombinator.com/item?id=8716977 https://news.ycombinator.com/item?id=8716977
- ec109685 10y agoIn the paper, they compromise not only the pgp key but also the Debian update server address, so all that is necessary is a software update to be compromised.
- willvarfar 10y agoAnother attack would be to flip bits in code pages... That the attackers illustrated it by changing public keys so they could push updates or ssh into a box doesn't mean that's all the ways they could have compromised. You can't say "I don't use SSH so I'm safe!" or anything like that.