Re: Whole Disk Encryption + SSD

From	<tomas@tuxteam.de>
Newsgroups	linux.debian.user
Subject	Re: Whole Disk Encryption + SSD
Date	2021-06-29 09:50 +0200
Message-ID	<CvgFj-2Ft-3@gated-at.bofh.it> (permalink)
References	<Cv0TT-1C0-3@gated-at.bofh.it> <Cv6cV-4QX-1@gated-at.bofh.it> <Cv9kt-6AU-1@gated-at.bofh.it>
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On Mon, Jun 28, 2021 at 07:56:47PM -0400, Stefan Monnier wrote:
> > Along with SED, I suggest that you also implement Secure Boot.
> 
> Can someone give me pointers to actually known attacks (not
> hypothetical ones, which I can invent myself without much difficulty)
> that would have been prevented by Secure Boot?

Basically, subverting the unencrypted loader amounts to what is known
as "evil maid attack" [1]: the most practical variant being that the
subverted loader records your passphrase (or whatever auth thingie you
provide) and either "phones home" or stashes it away in a place your
opponent can retrieve it.

The second time they have control over your device, they can unlock
the disk.

The whole thing is well described in Wikipedia [2], along with some
accounts of actual cases.

So /if/ you leave your laptop unsupervised and have the hunch that
someone might have a chance at it, make sure you reinstall :-)

There is another, low-tech alternative to the monstrous Secure
Boot [3] thingies bandied around here: carry your real boot partition
with you, either in an USB stick or (nicer form factor) an SD card.
Bonus points: you can leave a fake boot partition in your hard disk
which can be checked at each boot; if it changed, you can go "Hmmm...
someone tried to fool me..." and perhaps send them some passphrase.
The wrong one, of course.

Cheers

[1] Yes, a sexist term, but it stuck, unfortunately. OTOH, perhaps
   it's realistic in that it acknowledges that underpaid jobs are
   usually carried out by women. Sigh.

[2] https://en.wikipedia.org/wiki/Evil_maid_attack

[3] I always have the impression that, with Secure Boot, Microsoft
   has more control of the hardware (I paid for dearly, dammit!)
   than myself. Don't ask me why, but I thoroughly dislike that
   impression. So far I try to steer clear of it.

-- tomás

Thread

Whole Disk Encryption + SSD piorunz <piorunz@gmx.com> - 2021-06-28 17:00 +0200
  Re: Whole Disk Encryption + SSD Jochen Spieker <ml@well-adjusted.de> - 2021-06-28 18:00 +0200
  Re: Whole Disk Encryption + SSD David Christensen <dpchrist@holgerdanske.com> - 2021-06-28 22:40 +0200
    Re: Whole Disk Encryption + SSD David Christensen <dpchrist@holgerdanske.com> - 2021-06-29 00:00 +0200
    Re: Whole Disk Encryption + SSD Stefan Monnier <monnier@iro.umontreal.ca> - 2021-06-29 02:00 +0200
      Re: Whole Disk Encryption + SSD <tomas@tuxteam.de> - 2021-06-29 09:50 +0200
        Re: Whole Disk Encryption + SSD Stefan Monnier <monnier@iro.umontreal.ca> - 2021-06-30 00:50 +0200
        Re: Whole Disk Encryption + SSD David Christensen <dpchrist@holgerdanske.com> - 2021-06-30 01:00 +0200
    Re: Whole Disk Encryption + SSD Jonathan Dowland <jon+debian-user@dow.land> - 2021-06-29 11:30 +0200
    Re: Whole Disk Encryption + SSD piorunz <piorunz@gmx.com> - 2021-06-29 14:10 +0200
      Re: Whole Disk Encryption + SSD David Christensen <dpchrist@holgerdanske.com> - 2021-06-30 02:20 +0200
    Re: Whole Disk Encryption + SSD David Wright <deblis@lionunicorn.co.uk> - 2021-07-02 05:00 +0200
      Re: Whole Disk Encryption + SSD David Christensen <dpchrist@holgerdanske.com> - 2021-07-02 05:50 +0200
        Useless use of "dd" Teemu Likonen <tlikonen@iki.fi> - 2021-07-02 07:50 +0200
          Useful use of dd [was: Useless use of "dd"] <tomas@tuxteam.de> - 2021-07-02 09:50 +0200
            Re: Useful use of dd [was: Useless use of "dd"] Teemu Likonen <tlikonen@iki.fi> - 2021-07-02 12:30 +0200
              Re: Useful use of dd "Thomas Schmitt" <scdbackup@gmx.net> - 2021-07-02 13:00 +0200
                Re: Useful use of dd <tomas@tuxteam.de> - 2021-07-02 13:20 +0200
                Re: Useful use of dd Teemu Likonen <tlikonen@iki.fi> - 2021-07-02 13:30 +0200
                Re: Useful use of dd David Christensen <dpchrist@holgerdanske.com> - 2021-07-02 23:50 +0200
              Re: Useful use of dd [was: Useless use of "dd"] <tomas@tuxteam.de> - 2021-07-02 13:20 +0200
              Re: Useful use of dd Michael Stone <mstone@debian.org> - 2021-07-02 14:50 +0200
              Re: Useful use of dd [was: Useless use of "dd"] Kushal Kumaran <kushal@locationd.net> - 2021-07-02 21:10 +0200
                Creation of empty files [was: Useful use of dd] David Christensen <dpchrist@holgerdanske.com> - 2021-07-02 23:40 +0200
                Re: Creation of empty files [was: Useful use of dd] David Christensen <dpchrist@holgerdanske.com> - 2021-07-03 00:00 +0200
                Re: Creation of empty files [was: Useful use of dd] Michael Stone <mstone@debian.org> - 2021-07-03 15:50 +0200
                Re: Creation of empty files [was: Useful use of dd] David Christensen <dpchrist@holgerdanske.com> - 2021-07-03 23:40 +0200
                Re: Creation of empty files [was: Useful use of dd] Michael Stone <mstone@debian.org> - 2021-07-04 06:00 +0200
            Re: Useful use of dd [was: Useless use of "dd"] Greg Wooledge <greg@wooledge.org> - 2021-07-02 13:40 +0200
              Re: Useful use of dd [was: Useless use of "dd"] <tomas@tuxteam.de> - 2021-07-02 13:40 +0200
                Re: Useful use of dd [was: Useless use of "dd"] David Wright <deblis@lionunicorn.co.uk> - 2021-07-02 17:10 +0200
                Re: Useful use of dd [was: Useless use of "dd"] <tomas@tuxteam.de> - 2021-07-02 17:40 +0200
                Re: Useful use of dd [was: Useless use of "dd"] Gunnar Gervin <dofeelok@gmail.com> - 2021-07-03 09:20 +0200
                Re: Useful use of dd [was: Useless use of "dd"] <tomas@tuxteam.de> - 2021-07-03 09:30 +0200
            Useless use of shell pipelines [was: Useful use of dd] David Christensen <dpchrist@holgerdanske.com> - 2021-07-02 23:40 +0200
              Re: Useless use of shell pipelines [was: Useful use of dd] l0f4r0@tuta.io - 2021-07-03 10:30 +0200
                Re: Useless use of shell pipelines [was: Useful use of dd] Greg Wooledge <greg@wooledge.org> - 2021-07-03 15:40 +0200
          Re: Useless use of "dd" David Christensen <dpchrist@holgerdanske.com> - 2021-07-02 21:40 +0200
        Re: Whole Disk Encryption + SSD David Wright <deblis@lionunicorn.co.uk> - 2021-07-02 17:10 +0200
          Re: Whole Disk Encryption + SSD Michael Stone <mstone@debian.org> - 2021-07-02 17:30 +0200
          Re: Whole Disk Encryption + SSD David Christensen <dpchrist@holgerdanske.com> - 2021-07-02 20:40 +0200

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