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Re: Warning Linux Mint Website Hacked and ISOs replaced with Backdoored Operating System



Hi,

an interesting detail in advance:

It does not boot from USB stick. Too dumb for that.
>From DVD it boots only via BIOS or EFI BIOS emulation, not via
generic EFI.


I wrote:
> > ... google ... Kim Schmitz ... rofl ... i am not that curious.

Andrew McGlashan wrote:
> Actually he doesn't run mega.nz any longer and he has said that he
> wouldn't trust the site now due to current ownership 

Now is this what his public relations adviser told him to say ?

Sandboxing as good as possible ... iceweaseling with Javascript:
  https://mega.nz/#!QwY1EZKJ!GW1gLzXaOUo8sNGF-zddRLwgsfamZy7C5u0CARjaUs0

Now it wants me to download a plugin.
My gutt feeling is that i am short before winning a Darwin Award.

New approach:

  $ wget http://cdimage.debian.org/debian-cd/current-live/amd64/iso-hybrid/debian-live-8.3.0-amd64-xfce-desktop.iso

  $ wget http://cdimage.debian.org/debian-cd/current-live/amd64/iso-hybrid/SHA512SUMS.sign

  $ wget http://cdimage.debian.org/debian-cd/current-live/amd64/iso-hybrid/SHA512SUMS

  $ gpg --verify SHA512SUMS.sign SHA512SUMS
  gpg: Signature made Thu 28 Jan 2016 02:07:19 AM CET using RSA key ID 6294BE9B
  gpg: Good signature from "Debian CD signing key <debian-cd@lists.debian.org>"
  gpg: WARNING: This key is not certified with a trusted signature!
  gpg:          There is no indication that the signature belongs to the owner.

Well, my own key is not any better. To me this step is a ritual that
is applauded by people who are better informed than me. I consider
it more a social courtesy than a personal security feature.

  $ x=$(grep debian-live-8.3.0-amd64-xfce-desktop.iso'$' SHA512SUMS)
  $ echo "$x"
  1cead0dfde971e0c70145f6c908cea067ee7ee067f5ca481f076db78d99a99088be76737af4e2c9569540208d6e841f758a568ca12db077fa327e323b5da3a04  debian-live-8.3.0-amd64-xfce-desktop.iso

  $ y=$(sha512sum debian-live-8.3.0-amd64-xfce-desktop.iso)
  $ echo $y
  1cead0dfde971e0c70145f6c908cea067ee7ee067f5ca481f076db78d99a99088be76737af4e2c9569540208d6e841f758a568ca12db077fa327e323b5da3a04  debian-live-8.3.0-amd64-xfce-desktop.iso

  $ test "$x" = "$y" && echo All is well
  All is well

To the test machine ... iceweasel warns me duely that i am about
to shoot my foot ... now the plugin is at work. I just don't see any
file emerging in ~/Downloads.
That's really scary. Like an Android phone.
A large file emerges in ~/Desktop. (I am wearing my garlic necklace now,
spraying holy water, and looking up witch signs in the Malleus Maleficarum.)

Ok. It's downloaded and md5sum says 7d590864618866c225ede058f1ba61f0.
Copying it on a DVD, not as image but as data file inside an ISO.
So it cannot hop onto innocent machines just by being put into the
DVD drive.
Back on workstation ...

They used genisoimage:

  $ xorriso -indev ...long.name...iso -pvd_info
  ...
  Volume Id    : Linux Mint 17.3 Rosa 64-bit
  Volume Set Id: 
  Publisher Id : 
  Preparer Id  : 
  App Id       : GENISOIMAGE ISO 9660/HFS FILESYSTEM CREATOR (C) 1993 E.YOUNGDALE (C) 1997-2006 J.PEARSON/J.SCHILLING (C) 2006-2007 CDRKIT TEAM
  System Id    : LINUX
  CopyrightFile: 
  Abstract File: 
  Biblio File  : 
  Creation Time: 2016021909371600
  Cr. Time Zone: -05:00
  Modif. Time  : 2016021909371600
  Mo. Time Zone: -05:00
  Expir. Time  : 0000000000000000
  Eff. Time    : 2016021909371600
  Ef. Time Zone: -05:00

The sequence of SUSP fields indicates that it was indeed made by
a mkisofs clone.

Now for the original

  $ wget http://...mirror.../linuxmint-17.3-cinnamon-64bit.iso
  $ md5sum linuxmint-17.3-cinnamon-64bit.iso
  e71a2aad8b58605e906dbea444dc4983

This matches the MD5 on http://www.linuxmint.com/edition.php?id=204

  $ xorriso -indev linuxmint-17.3-cinnamon-64bit.iso -pvd_info
  ...
  Volume Id    : Linux Mint 17.3 Cinnamon 64-bit
  Volume Set Id: 
  Publisher Id : LINUX MINT
  Preparer Id  : LIVE-BUILD 3.0_A57-1
  App Id       : 
  System Id    : 
  CopyrightFile: 
  Abstract File: 
  Biblio File  : 
  Creation Time: 2015112815084800
  Modif. Time  : 2015112815084800
  Expir. Time  : 0000000000000000
  Eff. Time    : 0000000000000000

Ouch. They do not even have the same Volume Id (/dev/disk/by-label name).

The original was quite surely written by libisofs, probably under
control of xorriso. (Debian keeps my XORRISO branding in Preparer Id.)

Now for boot equipment:

  $ xorriso -hfsplus on -indev ...iso -report_el_torito plain -report_system_area plain
  ...
  Drive current: -indev 'compromised-linuxmint-17.3-cinnamon-64bit-7D590864618866C225EDE058F1BA61F0.iso'
  ...
  El Torito catalog  : 160  1
  El Torito cat path : /isolinux/boot.cat
  El Torito images   :   N  Pltf  B   Emul  Ld_seg  Hdpt  Ldsiz         LBA
  El Torito boot img :   1  BIOS  y   none  0x0000  0x00      4         161
  El Torito img path :   1  /isolinux/isolinux.bin
  El Torito img opts :   1  boot-info-table isohybrid-suitable
  ...
  xorriso : NOTE : No System Area was loaded

That's not even an isohybrid. No EFI equipment present either.
(The criminal must have read the most outdated recipes for bootable ISOs.) 

  $ xorriso -hfsplus on -indev linuxmint-17.3-cinnamon-64bit.iso -report_el_torito plain -report_system_area plain
  ...
  El Torito catalog  : 155  1
  El Torito cat path : /isolinux/boot.cat
  El Torito images   :   N  Pltf  B   Emul  Ld_seg  Hdpt  Ldsiz         LBA
  El Torito boot img :   1  BIOS  y   none  0x0000  0x00      4       17931
  El Torito boot img :   2  UEFI  y   none  0x0000  0x00   4544      769067
  El Torito img path :   1  /isolinux/isolinux.bin
  El Torito img opts :   1  boot-info-table isohybrid-suitable
  El Torito img path :   2  /boot/grub/efi.img
  System area options: 0x00000102
  System area summary: MBR isohybrid cyl-align-on GPT APM
  ISO image size/512 : 3088640
  Partition offset   : 0
  MBR heads per cyl  : 95
  MBR secs per head  : 32
  MBR partition table:   N Status  Type        Start       Blocks
  MBR partition      :   1   0x80  0x00            0      3088640
  MBR partition      :   2   0x00  0xef      3076268         4544
  MBR partition path :   2  /boot/grub/efi.img
  GPT                :   N  Info
  GPT disk GUID      :      fd922d606736564a9037adde0476578c
  GPT entry array    :      12  208  overlapping
  GPT lba range      :      64  3088586  3088639
  GPT partition name :   1  490053004f00480079006200720069006400
  GPT partname local :   1  ISOHybrid
  GPT partition GUID :   1  fd922d606736564a9035adde0476578c
  GPT type GUID      :   1  a2a0d0ebe5b9334487c068b6b72699c7
  GPT partition flags:   1  0x1000000000000001
  GPT start and size :   1  0  3088584
  GPT partition name :   2  490053004f004800790062007200690064003100
  GPT partname local :   2  ISOHybrid1
  GPT partition GUID :   2  fd922d606736564a9034adde0476578c
  GPT type GUID      :   2  a2a0d0ebe5b9334487c068b6b72699c7
  GPT partition flags:   2  0x1000000000000001
  GPT start and size :   2  3076268  4544
  GPT partition path :   2  /boot/grub/efi.img
  APM                :   N  Info
  APM block size     :      2048
  APM gap fillers    :      0
  APM partition name :   1  EFI
  APM partition type :   1  Apple_HFS
  APM start and size :   1  769067  1136
  APM partition path :   1  /boot/grub/efi.img

Yeah. That's how we learned it from Matthew Garrett.
(With some leanification in this case. Fedora Live CD has a HFS+
 filesystem image as third El Torito and as additional partition
 entry in the three partition maps.)

>From the viewpoint of my ivory tower i can confirm:
This attacker had no real clue about how to mimick a contemporary
installation ISO.

The fact that on the other hand the burglary was repeatedly successful,
gives me two theories:
- A script kiddy found a powerful intrusion program.
- An expert disguises as dumbnut. (For the fun of hearing the noise ?)


Have a nice day :)

Thomas
 


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