If you installed a Linux system with disk encryption...

If you installed a Linux system with disk encryption more than a couple of years ago, there's a decent chance it's using a weak key derivation function and someone who cares enough would be in a position to brute-force it. https://mjg59.dreamwidth.org/66429.html has more details and instructions on how to update to a better KDF.

Like 18 Apr 2023 at 0:28 | Open on nondeterministic.computer

13 comments

f00f/eris/continuum/etc

@mjg59 hmm

i wonder if my debian 12 install upgraded from a roughly year-old debian 11 is affected

18 Apr 2023 at 0:48 | Open on kind.social

anarcat

@f00fc7c8 @mjg59 to figure out if you're affected, run this: `cryptsetup luksDump /dev/sda3 | grep -e Version` and ` cryptsetup luksDump /dev/sda3 | grep PBKDF`. unless that says "2" and "argon2id", you are affected

18 Apr 2023 at 1:12 | Open on kolektiva.social

anarcat

@f00fc7c8 note that a previous reply of mine stated that you need to grep for Digests, that's explicitly what @mjg59 tells you *not* to do. in general, don't listen to me and listen to him

18 Apr 2023 at 1:18 | Open on kolektiva.social

itsybitesyspider :pmgpurple:

@f00fc7c8 @mjg59 I have a machine that I bought 21 months ago, that has only ever run debian unstable, and another from about 10 months ago, running stable, and both came back argon2i.

So this would seem to impact statistically everything.

18 Apr 2023 at 2:45 | Open on peoplemaking.games

f00f/eris/continuum/etc

@itsybitesyspider @mjg59 Hopefully this blog post gets major distros to push out argon2id by default as a security update.

18 Apr 2023 at 3:11 | Open on kind.social

🌻 Defederate Threads 🌻

@mjg59 Good to raise this point.

But the article assumes the encryption must have been broken. There are numerous other ways to get access to a computer's contents, ones which police heavily favor.

18 Apr 2023 at 1:15 | Open on infosec.exchange

unixbhaskar

@mjg59

Thanks for writing!

18 Apr 2023 at 1:22 | Open on mastodon.social

anarcat

@mjg59 i do wonder how one distribution (say Debian) is supposed to deal with this on upgrades... maybe we should add that to the release notes along with your procedure? i'm also considering doing such a procedure fleet-wide here... i can't help but think this is rather risky...