Re: Verified Boot, Secure Boot, dm-verity, debcheckroot

From	Elmar Stellnberger <estellnb@gmail.com>
Newsgroups	linux.debian.security
Subject	Re: Verified Boot, Secure Boot, dm-verity, debcheckroot
Date	2019-11-16 15:40 +0100
Message-ID	<z37oZ-3av-5@gated-at.bofh.it> (permalink)
References	(5 earlier) <yw4Uy-97-3@gated-at.bofh.it> <yycbg-wI-5@gated-at.bofh.it> <yymWZ-78w-1@gated-at.bofh.it> <z2Mue-7dA-9@gated-at.bofh.it> <z35Qd-240-1@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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> There are tools that can help with checking all files on the hard drive
> such as `debsums`. However, while `debsums` is more popular, it is
> unsuitable.
>
> Quote https://www.elstel.org/debcheckroot/
>
> ...
> During development of Verifiable Builds experiences were made with
> verification of MBR, VBR, bootloader, partition table, kernel and
> initrd. Source code was created to analyze such files.
>
> https://www.whonix.org/wiki/Verifiable_Builds

verifying the BIOS/UEFI:

Most of the computers I have support flashrom. Either I have added 
support on my own or I have bought machines that were known to support it.
If you take a malware image with debcheckroot you should possibly also 
add an image of your BIOS. I can report about the following discoveries:
Lately I have taken multiple BIOS images on a P5P41TUSB3, ASUS board:
* naturally that board does not boot from USB3
* some time I have found it to boot from sdcard but only when a certain 
hard disk was attached via usb3 ob boot time, the boot sector of that 
hard disk was blanked (containing zeroes).
   This discovery would strongly indicate that the BIOS was manipulated 
and that some boot code was fetched likely from the intermediate gaps in 
the partition table of that USB hard disk used for downloads with Tails
* some time later it did boot from any usb3 slot also from the usb3 
sdcard reader no matter what hard disk was attached
* now, since last week it does no more boot from usb3
If anyone wants to have these BIOS images I could upload them somewhere.
It is a question on how to determine if possibly malicious changes have 
been applied to a bios image.
I have used bindiff (https://www.elstel.org/qemu/) to list the number of 
bytes that differ between BIOS images.
- about 70 bytes differed between any two boots, even if you do not 
enter the BIOS settings
- after flashing a new BIOS with ASUS EZ+Flash, a BIOS internal flash 
utility a little more bytes differed, but not that many
- when leaving the computer alone for half a week far more bytes 
differed + the boot behaviour as described above

Thread

Have I caught a firmware attack in the act? Or am I just paranoid? "Rebecca N. Palmer" <rebecca_palmer@zoho.com> - 2019-08-13 09:40 +0200
  Re: Have I caught a firmware attack in the act? Or am I just paranoid? Paul Wise <pabs@debian.org> - 2019-08-14 07:10 +0200
  Re: Have I caught a firmware attack in the act? Or am I just  paranoid? Elmar Stellnberger <estellnb@gmail.com> - 2019-08-14 17:40 +0200
    Re: Have I caught a firmware attack in the act? Or am I just  paranoid? "Rebecca N. Palmer" <rebecca_palmer@zoho.com> - 2019-08-15 23:20 +0200
      Re: Have I caught a firmware attack in the act? Or am I just  paranoid? Davide Prina <davide.prina@gmail.com> - 2019-08-16 10:40 +0200
        Re: Have I caught a firmware attack in the act? Or am I just  paranoid? CMH <chouck@binghamton.edu> - 2019-08-16 14:20 +0200
        Re: Have I caught a firmware attack in the act? Or am I just paranoid? Andrei Grosu <andrei_grosu@fastmail.net> - 2019-08-16 19:20 +0200
        Re: Have I caught a firmware attack in the act? Or am I just  paranoid? Elmar Stellnberger <estellnb@gmail.com> - 2019-08-16 19:20 +0200
      Re: Have I caught a firmware attack in the act? Or am I just  paranoid? Elmar Stellnberger <estellnb@gmail.com> - 2019-08-16 19:10 +0200
      Re: Have I caught a firmware attack in the act? Or am I just  paranoid? Elmar Stellnberger <estellnb@gmail.com> - 2019-08-16 19:30 +0200
      Re: Have I caught a firmware attack in the act? Or am I just  paranoid? Elmar Stellnberger <estellnb@gmail.com> - 2019-08-16 21:20 +0200
        Re: Have I caught a firmware attack in the act? Or am I just  paranoid? "Rebecca N. Palmer" <rebecca_palmer@zoho.com> - 2019-08-17 11:50 +0200
          Re: Have I caught a firmware attack in the act? Or am I just  paranoid? Elmar Stellnberger <estellnb@gmail.com> - 2019-08-17 13:20 +0200
            Re: Have I caught a firmware attack in the act? Or am I just  paranoid? "Rebecca N. Palmer" <rebecca_palmer@zoho.com> - 2019-08-23 09:30 +0200
              Re: Have I caught a firmware attack in the act? Or am I just  paranoid? Elmar Stellnberger <estellnb@gmail.com> - 2019-08-23 21:00 +0200
                debcheckroot v2.0 released Elmar Stellnberger <estellnb@gmail.com> - 2019-11-15 17:20 +0100
                Verified Boot, Secure Boot, dm-verity, debcheckroot Patrick Schleizer <adrelanos@riseup.net> - 2019-11-16 14:00 +0100
                Re: Verified Boot, Secure Boot, dm-verity, debcheckroot Elmar Stellnberger <estellnb@gmail.com> - 2019-11-16 15:30 +0100
                Re: Verified Boot, Secure Boot, dm-verity, debcheckroot Sylvain Beucler <beuc@beuc.net> - 2019-11-16 15:40 +0100
                Re: Verified Boot, Secure Boot, dm-verity, debcheckroot Elmar Stellnberger <estellnb@gmail.com> - 2019-11-16 15:40 +0100
                Re: debcheckroot v2.0 released Patrick Schleizer <adrelanos@riseup.net> - 2019-11-19 13:40 +0100
                Re: debcheckroot v2.0 released Elmar Stellnberger <estellnb@gmail.com> - 2019-11-20 12:30 +0100
                Re: debcheckroot v2.0 released Patrick Schleizer <adrelanos@riseup.net> - 2019-11-25 12:40 +0100
                Re: debcheckroot v2.0 released Elmar Stellnberger <estellnb@gmail.com> - 2019-11-25 18:00 +0100
                Re: debcheckroot v2.0 released Elmar Stellnberger <estellnb@gmail.com> - 2019-12-10 17:40 +0100
                Re: debcheckroot v2.0 released Elmar Stellnberger <estellnb@gmail.com> - 2019-11-27 12:10 +0100
                Re: debcheckroot v2.0 released Cindy Sue Causey <butterflybytes@gmail.com> - 2020-01-17 14:40 +0100
                Re: debcheckroot v2.0 released Elmar Stellnberger <estellnb@gmail.com> - 2020-01-17 17:00 +0100
                Re: debcheckroot v2.0 released Elmar Stellnberger <estellnb@gmail.com> - 2020-01-17 17:20 +0100
                Re: debcheckroot v2.0 released Elmar Stellnberger <estellnb@gmail.com> - 2020-03-04 20:20 +0100
                Re: debcheckroot v2.0 released Elmar Stellnberger <estellnb@gmail.com> - 2020-03-04 20:50 +0100
                Re: debcheckroot v2.0 released Elmar Stellnberger <estellnb@gmail.com> - 2020-03-04 21:00 +0100
                Re: debcheckroot v2.0 released Elmar Stellnberger <estellnb@gmail.com> - 2020-03-04 21:00 +0100
                Re: debcheckroot v2.0 released Elmar Stellnberger <estellnb@gmail.com> - 2020-03-23 17:10 +0100
                Re: debcheckroot v2.0 released Paul Wise <pabs@debian.org> - 2020-03-24 04:40 +0100
                Re: debcheckroot v2.0 released Paul Wise <pabs@debian.org> - 2020-03-24 11:20 +0100
                Re: debcheckroot v2.0 released Elmar Stellnberger <estellnb@elstel.org> - 2020-03-24 15:50 +0100
                Re: debcheckroot v2.0 released Paul Wise <pabs@debian.org> - 2020-03-25 03:00 +0100
                Re: debcheckroot v2.0 released Elmar Stellnberger <estellnb@elstel.org> - 2020-03-25 11:30 +0100
                Re: debcheckroot v2.0 released Elmar Stellnberger <estellnb@elstel.org> - 2020-03-26 11:10 +0100
                Re: debcheckroot v2.0 released "vince@vheuser.com" <vince@vheuser.com> - 2020-04-01 20:10 +0200
                Re: debcheckroot v2.0 released Paul Wise <pabs@debian.org> - 2020-04-02 02:00 +0200
                Re: debcheckroot v2.0 released Lewis Yarema <lewisyarema91@gmail.com> - 2020-04-02 11:20 +0200
                Re: debcheckroot v2.0 released Elmar Stellnberger <estellnb@elstel.org> - 2020-04-02 17:00 +0200
                Re: debcheckroot v2.0 released Elmar Stellnberger <estellnb@elstel.org> - 2020-04-03 13:40 +0200
                Re: debcheckroot v2.0 released Elmar Stellnberger <estellnb@elstel.org> - 2020-04-02 16:50 +0200
                Re: debcheckroot v2.0 released Elmar Stellnberger <estellnb@elstel.org> - 2020-04-04 09:50 +0200
                Re: debcheckroot v2.0 released William Gagnebé <william.gagnebe@gmail.com> - 2020-04-05 12:20 +0200
                Re: debcheckroot v2.0 released l0f4r0@tuta.io - 2020-04-05 12:30 +0200
                Re: debcheckroot v2.0 released Elmar Stellnberger <estellnb@elstel.org> - 2020-04-07 17:50 +0200
                Re: debcheckroot v2.0 released "Niall O'Reilly" <Niall.oReilly+lists@no8.be> - 2020-04-02 18:30 +0200
                Re: debcheckroot v2.0 released Lee <ler762@gmail.com> - 2020-04-02 21:00 +0200
                Re: debcheckroot v2.0 released Elmar Stellnberger <estellnb@elstel.org> - 2020-04-02 21:40 +0200
                Re: debcheckroot v2.0 released Elmar Stellnberger <estellnb@elstel.org> - 2020-04-03 13:50 +0200
                Re: debcheckroot v2.0 released Lee <ler762@gmail.com> - 2020-04-04 00:50 +0200
                Re: debcheckroot v2.0 released Elmar Stellnberger <estellnb@elstel.org> - 2020-04-04 09:40 +0200
                Re: debcheckroot v2.0 released Bjørn Mork <bjorn@mork.no> - 2020-04-14 09:30 +0200
                arbitrary code execution on unformatted usb stick Elmar Stellnberger <estellnb@elstel.org> - 2020-04-25 15:40 +0200
                Re: arbitrary code execution on unformatted usb stick Elmar Stellnberger <estellnb@elstel.org> - 2020-04-25 15:50 +0200
                Re: arbitrary code execution on unformatted usb stick Elmar Stellnberger <estellnb@elstel.org> - 2020-05-02 17:00 +0200
                Re: arbitrary code execution on unformatted usb stick Elmar Stellnberger <estellnb@elstel.org> - 2020-05-02 17:10 +0200
                Fwd: Re: arbitrary code execution on unformatted usb stick estellnb@elstel.org - 2020-05-02 20:50 +0200
                Re: debcheckroot v2.0 released Elmar Stellnberger <estellnb@gmail.com> - 2020-03-21 17:40 +0100
      Probably a false alarm Re: Have I caught a firmware attack in the  act? Or am I just paranoid? "Rebecca N. Palmer" <rebecca_palmer@zoho.com> - 2019-08-24 18:50 +0200

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