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agherzan / yubikey-full-disk-encryption

Use YubiKey to unlock a LUKS partition
Apache License 2.0
821 stars 51 forks source link

Challenge exposed in process list #44

Closed HacKanCuBa closed 5 years ago

HacKanCuBa commented 5 years ago

Hello there! I was checking your scripts and I noticed that you pass the password to the ykchalresp bin as part of its command line, thus exposing it to the system: https://github.com/agherzan/yubikey-full-disk-encryption/blob/0e1e58b9b90eef318d17e0ceb4f267063d1d864b/src/ykfde-enroll#L149

If you run top or htop you will see the password shows up there. The same happens in the initram script, but on that scenario is not so dangerous. However, on the already booted up scenario, having the password shown as part of the command is VERY dangerous.

I haven't used ykchalresp but a better approach would be to pass the password like: printf "%s" "$P1" | ykchalresp -2 - or something like that (we need to test this).

HacKanCuBa commented 5 years ago

BTW, this code is somewhat similar to cornelinux/yubikey-luks, and thus has this same issue.

Vincent43 commented 5 years ago

@HacKanCuBa great find! I'll look into it.

Vincent43 commented 5 years ago

@HacKanCuBa This should be fixed in https://github.com/agherzan/yubikey-full-disk-encryption/commit/6aa15b9ddc9ce3d6f2fc1aa6b79842d4afe76f83 . Thank you again for reporting this.

HacKanCuBa commented 5 years ago

Awesome! I checked the commit and seems fine.

Thank you!

agherzan commented 5 years ago

Nice report!