delete deleted data

[Marco Peereboom]

Grind them up.  There is nothing else you can do to "permanently" wipe
disks.  Residual magnetism is always there provided good enough
equipment.  If your data is that sensitive there is nothing else but the
grinder.

On Mon, Dec 31, 2007 at 10:25:25AM -0800, Jon wrote:

> hi
>
>  I see a lot of programs that are available to clean up the disks for
> Windows OS. Not wipe a disk but clean up deleted files so they cannot be
> recovered.
>  Is there any program for OpenBSD that will clean up the disks so that
> deleted files cannot be recovered.
>
>  (not looking to delete a file securly - but to wipe the disk clean of
> deleted file with out affecting the OS)
>
> -jon

[Jon-113]

hi

 I see a lot of programs that are available to clean up the disks for
Windows OS. Not wipe a disk but clean up deleted files so they cannot be
recovered.
 Is there any program for OpenBSD that will clean up the disks so that
deleted files cannot be recovered.

 (not looking to delete a file securly - but to wipe the disk clean of
deleted file with out affecting the OS)

-jon

[Steve Shockley]

Jon wrote:
>  (not looking to delete a file securly - but to wipe the disk clean of
> deleted file with out affecting the OS)

What problem are you trying to solve?

[Hannah Schroeter]

Hi!

On Mon, Dec 31, 2007 at 10:25:25AM -0800, Jon wrote:
> I see a lot of programs that are available to clean up the disks for
>Windows OS. Not wipe a disk but clean up deleted files so they cannot be
>recovered.
> Is there any program for OpenBSD that will clean up the disks so that
>deleted files cannot be recovered.

> (not looking to delete a file securly - but to wipe the disk clean of
>deleted file with out affecting the OS)

dd if=/dev/zero of=/mount/point/something bs=1024k

(wait until disk is full)

rm /mount/point/something

>-jon

Kind regards,

Hannah.

[Nick Guenther]

But as a stopgap, look into rm -P (on OpenBSD). Linux has "shred" too.

On Dec 31, 2007 1:25 PM, Marco Peereboom <slash@...> wrote:

> Grind them up.  There is nothing else you can do to "permanently" wipe
> disks.  Residual magnetism is always there provided good enough
> equipment.  If your data is that sensitive there is nothing else but the
> grinder.
>
> On Mon, Dec 31, 2007 at 10:25:25AM -0800, Jon wrote:
>
> > hi
> >
> >  I see a lot of programs that are available to clean up the disks for
> > Windows OS. Not wipe a disk but clean up deleted files so they cannot be
> > recovered.
> >  Is there any program for OpenBSD that will clean up the disks so that
> > deleted files cannot be recovered.
> >
> >  (not looking to delete a file securly - but to wipe the disk clean of
> > deleted file with out affecting the OS)
> >
> > -jon

[new_guy]

Jon-113 wrote:

Is there any program for OpenBSD that will clean up the disks so that
deleted files cannot be recovered.

/dev/zero or /dev/urandom either will work fine (the first being quicker than the last)

[xSAPPYx]

On Dec 31, 2007 10:25 AM, Marco Peereboom <slash@...> wrote:
> Grind them up.  There is nothing else you can do to "permanently" wipe
> disks.  Residual magnetism is always there provided good enough
> equipment.  If your data is that sensitive there is nothing else but the
> grinder.

Someone linked me this article a couple calling into question the
ability to actually read overwritten data:
http://www.nber.org/sys-admin/overwritten-data-guttman.html

I'de love to read something from the other side, showing real examples
of getting usable data off of a disk that has been overwritten / wiped
/ etc

any links or info?

[new_guy]

xSAPPYx wrote:

Someone linked me this article a couple calling into question the
ability to actually read overwritten data:
http://www.nber.org/sys-admin/overwritten-data-guttman.html

I'de love to read something from the other side, showing real examples
of getting usable data off of a disk that has been overwritten / wiped
/ etc

any links or info?

Not possible on today's drives. In fact, according to NIST, one overwrite with only zeros is sufficient. See The National Institute of Standards and Technology (NIST) Special Publication 800-88, "Guidelines for Media Sanitation."

[new_guy]

Marco Peereboom wrote:

Grind them up.  There is nothing else you can do to "permanently" wipe
disks.  Residual magnetism is always there provided good enough
equipment.  If your data is that sensitive there is nothing else but the
grinder.

Be sure that you do this yourself or personally witness the act. I just experienced this myself where a contractor was *paid* money to grind up hard drives in a bunch of old Sun hardware before the equipment was auctioned off online. The contractor even issued 'certificates of destruction' for the drives... long story short, the drives had not been destroyed. They were intact, untouched, not even a software wipe. The drives booted and worked fine. A simple 'boot cdrom -s' to change the root passwd was all it took to view the hard drive's content.

[Unix Fan]

"rm -P" would be what you're looking for..



But is it even required? It's not exactly an easy task to "undelete" a file anyway... the process alone is an effecitve deterrent.



-Nix Fan.

[mbrown-2]

Some geeks have had hard drive roast featuring thermite placed on top of hard drives to melt them.

That sounds like a fun way to securely delete data given enough thermite.

--- Marina Brown
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Date: Mon, 31 Dec 2007 12:25:02 -0600
From: Marco Peereboom <slash@...>
To: Jon <hypermails@...>
Cc: misc@...
Subject: Re: delete deleted data
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Grind them up.  There is nothing else you can do to "permanently" wipe
disks.  Residual magnetism is always there provided good enough
equipment.  If your data is that sensitive there is nothing else but the
grinder.

On Mon, Dec 31, 2007 at 10:25:25AM -0800, Jon wrote:

> hi
>
>  I see a lot of programs that are available to clean up the disks for
> Windows OS. Not wipe a disk but clean up deleted files so they cannot be
> recovered.
>  Is there any program for OpenBSD that will clean up the disks so that
> deleted files cannot be recovered.
>
>  (not looking to delete a file securly - but to wipe the disk clean of
> deleted file with out affecting the OS)
>
> -jon

[j4nKy]

On Mon, Dec 31, 2007 at 04:32:08PM -0500, mbrown@... wrote:
> Some geeks have had hard drive roast featuring thermite placed on top of hard drives to melt them.
>
> That sounds like a fun way to securely delete data given enough thermite.

nah, use one of these http://www.glasstorchtech.com/torches.html
the Mirage will liquify the platters in about 40 seconds ... smells
kinda bad though.

--
jakemsr@...
SDF Public Access UNIX System - http://sdf.lonestar.org

[Marco Peereboom]

bullshit.

On Mon, Dec 31, 2007 at 12:56:54PM -0800, new_guy wrote:

> xSAPPYx wrote:
> >
> > Someone linked me this article a couple calling into question the
> > ability to actually read overwritten data:
> > http://www.nber.org/sys-admin/overwritten-data-guttman.html
> >
> > I'de love to read something from the other side, showing real examples
> > of getting usable data off of a disk that has been overwritten / wiped
> > / etc
> >
> > any links or info?
> >
>
> Not possible on today's drives. In fact, according to NIST, one overwrite
> with only zeros is sufficient. See The National Institute of Standards and
> Technology (NIST) Special Publication 800-88, "Guidelines for Media
> Sanitation."
>
> --
> View this message in context: http://www.nabble.com/delete-deleted-data-tp14560809p14561973.html
> Sent from the openbsd user - misc mailing list archive at Nabble.com.

[Darrin Chandler]

To expand on "bullshit" a little...

The longer you leave a 0 or 1 in a given place on a platter the more of
an "impression" it makes there. Writing over it with with random bits,
even several times, will not totally erase the deep magnetic impression
of the former bit. Forensics are more than good enough to pick that up,
if you pay the money.

As always, the real question becomes how much of a chance is there of
someone getting an old hard disk, and how much damage would be done if
they read the data on it. This is where is usually falls apart. People
want to completely wipe a disk, but want that to be essentially free in
cost and hassle. Tough cookies. If it's worth it, then completely
destroy the drives. If it's not worth it then write random data on it a
few times and call it good. But make an informed choice. Writing random
data might stop joe blow, but it won't stop someone serious with a lot
to gain.

On Mon, Dec 31, 2007 at 05:36:46PM -0600, Marco Peereboom wrote:

> bullshit.
>
> On Mon, Dec 31, 2007 at 12:56:54PM -0800, new_guy wrote:
> > xSAPPYx wrote:
> > >
> > > Someone linked me this article a couple calling into question the
> > > ability to actually read overwritten data:
> > > http://www.nber.org/sys-admin/overwritten-data-guttman.html
> > >
> > > I'de love to read something from the other side, showing real examples
> > > of getting usable data off of a disk that has been overwritten / wiped
> > > / etc
> > >
> > > any links or info?
> > >
> >
> > Not possible on today's drives. In fact, according to NIST, one overwrite
> > with only zeros is sufficient. See The National Institute of Standards and
> > Technology (NIST) Special Publication 800-88, "Guidelines for Media
> > Sanitation."
> >
> > --
> > View this message in context: http://www.nabble.com/delete-deleted-data-tp14560809p14561973.html
> > Sent from the openbsd user - misc mailing list archive at Nabble.com.
>

--
Darrin Chandler            |  Phoenix BSD User Group  |  MetaBUG
dwchandler@...   |  http://phxbug.org/      |  http://metabug.org/
http://www.stilyagin.com/  |  Daemons in the Desert   |  Global BUG Federation

[Jon-113]

hi

the problem is to clean up the un-used storage locations. When I delete
files / logs/ etc... I don't want any one to recover them. I am not asking
how to securly discard my disks...

 The answers are (from the threads)

    1. rm -P
    2. fill up the disks with 0 and delete them when the disk is full or
near full

I am not looking for how to grind the disks or hammer the. How to get some
one to dispose of the hard disks..
Again, Is there a way to wipe the un-used space in my hard disks clean with
out afftecting the OS ?

-jon

On Dec 31, 2007 10:25 AM, Jon <hypermails@... > wrote:

> hi
>
>  I see a lot of programs that are available to clean up the disks for
> Windows OS. Not wipe a disk but clean up deleted files so they cannot be
> recovered.
>  Is there any program for OpenBSD that will clean up the disks so that
> deleted files cannot be recovered.
>
>  (not looking to delete a file securly - but to wipe the disk clean of
> deleted file with out affecting the OS)
>
> -jon

[daemon1]

On Dec 31, 2007, at 11:19 PM, Jon wrote:

> hi
>
> the problem is to clean up the un-used storage locations. When I  
> delete
> files / logs/ etc... I don't want any one to recover them. I am not  
> asking
> how to securly discard my disks...
>
>  The answers are (from the threads)
>
>     1. rm -P
>     2. fill up the disks with 0 and delete them when the disk is  
> full or
> near full
>
> I am not looking for how to grind the disks or hammer the. How to  
> get some
> one to dispose of the hard disks..
> Again, Is there a way to wipe the un-used space in my hard disks  
> clean with
> out afftecting the OS ?
>
> -jon
>

Then it appears that you have your answer(s)

-Jonathan

[Christopher Linn]

On Mon, Dec 31, 2007 at 12:25:02PM -0600, Marco Peereboom wrote:

> On Mon, Dec 31, 2007 at 10:25:25AM -0800, Jon wrote:
> > hi
> >
> >  I see a lot of programs that are available to clean up the disks for
> > Windows OS. Not wipe a disk but clean up deleted files so they cannot be
> > recovered.
> >  Is there any program for OpenBSD that will clean up the disks so that
> > deleted files cannot be recovered.
> >
> >  (not looking to delete a file securly - but to wipe the disk clean of
> > deleted file with out affecting the OS)
> >
> > -jon
>
> Grind them up.  There is nothing else you can do to "permanently" wipe
> disks.  Residual magnetism is always there provided good enough
> equipment.  If your data is that sensitive there is nothing else but the
> grinder.
>

put a wood furnace in you garage, get a good hardwood fire going, pop
the disk in there, and stoak it again in 2 hours. there you go.

cel

--
Christopher Linn <celinn at mtu.edu>  | By no means shall either the CEC
System Administrator II               | or MTU be held in any way liable
  Center for Experimental Computation | for any opinions or conjecture I
    Michigan Technological University | hold to or imply to hold herein.

[Douglas A. Tutty]

On Tue, Jan 01, 2008 at 02:14:53PM -0500, Christopher Linn wrote:

> On Mon, Dec 31, 2007 at 12:25:02PM -0600, Marco Peereboom wrote:
> > On Mon, Dec 31, 2007 at 10:25:25AM -0800, Jon wrote:
> > >
> > >  I see a lot of programs that are available to clean up the disks for
> > > Windows OS. Not wipe a disk but clean up deleted files so they cannot be
> > > recovered.
> > >  Is there any program for OpenBSD that will clean up the disks so that
> > > deleted files cannot be recovered.
> > >
> > >  (not looking to delete a file securly - but to wipe the disk clean of
> > > deleted file with out affecting the OS)
> >
> > Grind them up.  There is nothing else you can do to "permanently" wipe
> > disks.  Residual magnetism is always there provided good enough
> > equipment.  If your data is that sensitive there is nothing else but the
> > grinder.
> >
> put a wood furnace in you garage, get a good hardwood fire going, pop
> the disk in there, and stoak it again in 2 hours. there you go.

Of course, both the grinder and the fire will have a negative effect on
the OS installed on the drive :)

Note that if you do choose the fire method, that there are components
in the drive that you don't need to burn in order to securely delete
data.  Burning them will have a negative impact on the environment and
perhaps on the stove.  All you really need to do is burn the oxide off
the platters.  If the platters are aluminum, it shouldn't be too
difficult to melt the platters but I don't know if that will render the
oxide coating inoperable or if it just comes off as a sheet that could
be read.

Perhaps you need to grind up the platters into powder, mix in some
powdered nitrogen fertilizer, and explode it with your annual fireworks
:)

Doug.

[Marco Peereboom]

Still recoverable.  I have dealt with pretty badly burnt disks that we
recovered data off.  Really the grinder is the way to go.

On Tue, Jan 01, 2008 at 02:14:53PM -0500, Christopher Linn wrote:

> On Mon, Dec 31, 2007 at 12:25:02PM -0600, Marco Peereboom wrote:
> > On Mon, Dec 31, 2007 at 10:25:25AM -0800, Jon wrote:
> > > hi
> > >
> > >  I see a lot of programs that are available to clean up the disks for
> > > Windows OS. Not wipe a disk but clean up deleted files so they cannot be
> > > recovered.
> > >  Is there any program for OpenBSD that will clean up the disks so that
> > > deleted files cannot be recovered.
> > >
> > >  (not looking to delete a file securly - but to wipe the disk clean of
> > > deleted file with out affecting the OS)
> > >
> > > -jon
> >
> > Grind them up.  There is nothing else you can do to "permanently" wipe
> > disks.  Residual magnetism is always there provided good enough
> > equipment.  If your data is that sensitive there is nothing else but the
> > grinder.
> >
>
> put a wood furnace in you garage, get a good hardwood fire going, pop
> the disk in there, and stoak it again in 2 hours. there you go.
>
> cel
>
> --
> Christopher Linn <celinn at mtu.edu>  | By no means shall either the CEC
> System Administrator II               | or MTU be held in any way liable
>   Center for Experimental Computation | for any opinions or conjecture I
>     Michigan Technological University | hold to or imply to hold herein.

[Hannah Schroeter]

Hi!

On Tue, Jan 01, 2008 at 05:27:59PM -0600, Marco Peereboom wrote:
>Still recoverable.  I have dealt with pretty badly burnt disks that we
>recovered data off.  Really the grinder is the way to go.

Thermite should do the work too. Hot enough to bring the material out of
the ferromagnetic temperature range, i.e. to lose its magnetization.

And nice special fx. *g*

Grinding leaves small pieces of still magnetized material where a
*very* determined (yeah, unlikely unless the data is worth *very*
much) attacker could try playing jigsaw puzzle.

Of course you could try combining a grinding and a demagnetizing
technique (for the latter I'm still partial with applying heat that
brings the material well out of the ferromagnetic range).

Kind regards,

Hannah.