Re: vulnerability in Linux Debian default boot configuration

From: Ben Collins (bcollinsat_private)
Date: Thu Feb 03 2000 - 10:37:46 PST

  • Next message: Marc Slemko: "Re: Fwd: CERT Advisory CA-2000-02"

    --LQksG6bCIzRHxTLp
    Content-Type: text/plain; charset=us-ascii
    Content-Transfer-Encoding: quoted-printable
    
    Just a quick comment. This was discussed (if you call a flame fest a
    discussion) to a great extent on Debian's list. To sum up the discussion:
    
    a) The boot floppies were changed after this for potato to make sure the
       user knows about the default setup (the MBR that allows booting from
       floppy).
    
    b) The vast majority of systems do not require physical security in this
       manner, and the benefits for rescueing failed systems using this
       feature outweighs the downside of the "issue".
    
    c) It is felt that an admin who is first of all smart enough to setup the
       BIOS and LILO to disable floppy booting, and is in dire need enough to
       want this, should also be intelligent enough to know that the MBR is
       part of the boot process, and thus they should expect to make changes
       there aswell.
    
    d) Given that 99.9% of computer systems are setup to not disable floppy
       booting (forsaking the obviously biased percentage of people on this
       list who do have it disabled), that it is not a problem to also have
       this as the default.
    
    e) Anyone who wants true physical security will use physical measures to
       assure it. This means locked cases, locked racks, removing the floppy
       alltogether. Thus the MBR plays a minor role in this type of security.
    
    f) RTFM. The mbr program docs, and the LILO docs explain about the MBR and
       security concerns dealing with it. Even disabling the floppy does not
       assure physical security in a public manner (such as the machines that
       the original poster is using...eg. publically accesable terminals).
    
    Thanks,
      Ben
    
    PS: I am not subscribed to BUGTRAQ at the moment, so please Cc questions.
    concerns.
    
    --=20
     -----------=3D=3D=3D=3D=3D=3D=3D-=3D-=3D=3D=3D=3D=3D=3D-=3D=3D=3D=3D=3D=3D=
    =3D=3D=3D-----------=3D=3D=3D=3D=3D------------=3D-=3D------
    /  Ben Collins  --  ...on that fantastic voyage...  --  Debian GNU/Linux   \
    `     bcollinsat_private  --  bcollinsat_private  --  bmcat_private     '
     `---=3D=3D=3D=3D=3D=3D=3D=3D=3D------=3D=3D=3D=3D=3D=3D=3D-------------=3D=
    -=3D-----=3D-=3D=3D=3D-=3D=3D=3D=3D=3D=3D-------=3D--=3D---'
    
    --LQksG6bCIzRHxTLp
    Content-Type: application/pgp-signature
    
    -----BEGIN PGP SIGNATURE-----
    Version: GnuPG v1.0.1 (GNU/Linux)
    Comment: Some people are fools, some are just foolish
    
    iD8DBQE4mcr5fNc/ZB4E7C0RAVmMAKCOIo7xIj6h/V9zxzOcVeo4hU9hxQCcCW8K
    VSE3LqLSvM02IhCyaW6QZfk=
    =KzS7
    -----END PGP SIGNATURE-----
    
    --LQksG6bCIzRHxTLp--
    



    This archive was generated by hypermail 2b30 : Fri Apr 13 2001 - 15:33:26 PDT