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I'm curious how practical an RNG attack actually is here (which absolutely isn't meant to serve as criticism of your surfacing the issue!). In any case, I expe
by dllthomas 6y ago
I'm curious how practical an RNG attack actually is here (which absolutely isn't meant to serve as criticism of your surfacing the issue!).
In any case, I expect it's much harder than a random "free password gen!" website saving results on the sly (... which is meant to be mild criticism of your framing, but not your recommendation :-p).
- rmrfstar 6y agoDepends on the situation. I definitely wouldn't try this on a freshly booted Raspberry Pi, for example.
- ThA0x2 6y agoshuf uses randint(), which defaults to /dev/urandom as the nonce source: https://github.com/coreutils/coreutils/blob/v8.31/gl/lib/randread.c https://github.com/coreutils/coreutils/blob/v8.31/gl/lib/ran... It's going to be as practical to attack as anything that uses /dev/urandom.
- dllthomas 6y agoFor sufficiently recent versions of shuf. It looks (... at a skim of the history, I could be confused) like older versions use pid, ppid, uid, gid, and time. In that case that's likely to be more practical than brute force if you've generated a password with notionally more than ~40 bits of entropy. That said, I suspect most people are indeed on a platform with a sufficiently recent version of shuf. (And a sufficiently old version may lack the random-source option.)
- ThA0x2 6y agoRHEL 6 will be EOLd this November. That's the last supported version of RHEL that has this issue. Ubuntu 13.04, RHEL 7 and later don't suffer from this issue. I'd say almost everyone reading these comments is on a platform that does not suffer from this issue.
- deleted 6y ago[deleted]