OT: Can Reformatting A Hard Drive To ext3 Destroy All the Data On It?

[Robert L Cochran]

I have a hard drive that I need to destroy the data on. What is the most 
dependable way to do this? Can reformatting the drive as ext3 or ext4 or 
some other filesystem effectively destroy the existing data?

Is there free software that can write zeroes or some form of nonsense to 
every storage location?

Thanks

Bob Cochran

[Sam Varshavchik]

Robert L Cochran writes:
> I have a hard drive that I need to destroy the data on. What is the most 
> dependable way to do this? Can reformatting the drive as ext3 or ext4 or 
> some other filesystem effectively destroy the existing data?
>
> Is there free software that can write zeroes or some form of nonsense to 
> every storage location?

dd if=/dev/zero of=/dev/youbettergetthisright bs=1M

[Arthur Pemberton]

On Thu, May 28, 2009 at 9:29 PM, Robert L Cochran
 wrote:
> I have a hard drive that I need to destroy the data on. What is the most
> dependable way to do this? Can reformatting the drive as ext3 or ext4 or
> some other filesystem effectively destroy the existing data?
>
> Is there free software that can write zeroes or some form of nonsense to
> every storage location?
>
> Thanks
>
> Bob Cochran

You can also use the badblocks program in write mode which writes a
repeated random sequence to the drive

[Clint Dilks]

Sam Varshavchik wrote:
> Robert L Cochran writes:
> > I have a hard drive that I need to destroy the data on. What is the 
> > most dependable way to do this? Can reformatting the drive as ext3 or 
> > ext4 or some other filesystem effectively destroy the existing data?
> >
> > Is there free software that can write zeroes or some form of nonsense 
> > to every storage location?
>
> dd if=/dev/zero of=/dev/youbettergetthisright bs=1M

If you want to be really sure you need to do the command above several 
time or use software like

http://www.dban.org/

[Gene Heskett]

On Thursday 28 May 2009, Robert L Cochran wrote:
> I have a hard drive that I need to destroy the data on. What is the most
> dependable way to do this? Can reformatting the drive as ext3 or ext4 or
> some other filesystem effectively destroy the existing data?
>
> Is there free software that can write zeroes or some form of nonsense to
> every storage location?

dd if=/dev/urandom of=/dev/(ice) repeated 3 or so times should pretty well 
destroy any attempts to recover any valid data from that drive.  Don't use the 
partition, such as /dev/sda1, but the whole drive, /dev/sda which should also 
get the partition tables.

Formatting a hard drive just installs a new inode framework and root 
directory.  The data itself is still there for something as simple as:
dd if=/dev/sdX
which will spit it all out to the screen with only the holes created by the 
installation of a new filesystem framework being invalid.

But /dev/urandom written to everything 3 or more times should render the data 
unrecoverable unless they wanna call out the guys with the electron 
microscopes to read the edges of the track byte by byte.
> Thanks
>
> Bob Cochran

[Stuart Munro]

Bob

I have used this utility before with good success 
http://www.soft32.com/download_191651.html

I have used this one with greater success 
http://www.killdisk.com/?gclid=CKatoNLX4JoCFQENDQodO0xTAQ

both are free utilities

-----Original Message-----
From: [e-mail] [mailto:[e-mail]]
On Behalf Of Gene Heskett
Sent: Thursday, May 28, 2009 10:54 PM
To: Community assistance, encouragement, and advice for using Fedora.
Subject: Re: OT: Can Reformatting A Hard Drive To ext3 Destroy All the Data
On It?

On Thursday 28 May 2009, Robert L Cochran wrote:
> I have a hard drive that I need to destroy the data on. What is the most
> dependable way to do this? Can reformatting the drive as ext3 or ext4 or
> some other filesystem effectively destroy the existing data?
>
> Is there free software that can write zeroes or some form of nonsense to
> every storage location?

dd if=/dev/urandom of=/dev/(ice) repeated 3 or so times should pretty well 
destroy any attempts to recover any valid data from that drive.  Don't use
the 
partition, such as /dev/sda1, but the whole drive, /dev/sda which should
also 
get the partition tables.

Formatting a hard drive just installs a new inode framework and root 
directory.  The data itself is still there for something as simple as:
dd if=/dev/sdX
which will spit it all out to the screen with only the holes created by the 
installation of a new filesystem framework being invalid.

But /dev/urandom written to everything 3 or more times should render the
data 
unrecoverable unless they wanna call out the guys with the electron 
microscopes to read the edges of the track byte by byte.
> Thanks
>
> Bob Cochran

[Alan Cox]

On Thu, 28 May 2009 22:29:23 -0400
Robert L Cochran  wrote:
> I have a hard drive that I need to destroy the data on. What is the most 
> dependable way to do this?

Thermite ?
> Can reformatting the drive as ext3 or ext4 or 
> some other filesystem effectively destroy the existing data?

No
> Is there free software that can write zeroes or some form of nonsense to 
> every storage location?

That isn't completely guaranteed. Modern drives have a security erase
command which I think some tools like hdparm can issue as shipped nowdays

[Ambrogio]

Il giorno ven, 29/05/2009 alle 14.52 +1200, Clint Dilks ha scritto:
> > dd if=/dev/zero of=/dev/youbettergetthisright bs=1M
>
> If you want to be really sure you need to do the command above several 
> time or use software like
>
> http://www.dban.org/

/dev/zero is not the right device to use.
Better is /dev/random or /dev/urandom
But they are not speed

Bye
 Ambrogio

[Frank Murphy]

Robert L Cochran wrote:
> I have a hard drive that I need to destroy the data on. What is the most 
> dependable way to do this? Can reformatting the drive as ext3 or ext4 or 
> some other filesystem effectively destroy the existing data?
>
> Is there free software that can write zeroes or some form of nonsense to 
> every storage location?
>
> Thanks
>
> Bob Cochran

Anglegrinder or Drill lots of holes.

FRank

[Alan Cox]

> /dev/zero is not the right device to use.
> Better is /dev/random or /dev/urandom
> But they are not speed

It makes no real difference - use the drives own secure erase feature if
you want to be sure, otherwise you've got no guarantee that everything
will be cleared - only the drive knows enough to do the job.

[Robin Laing]

Robert L Cochran wrote:
> I have a hard drive that I need to destroy the data on. What is the most 
> dependable way to do this? Can reformatting the drive as ext3 or ext4 or 
> some other filesystem effectively destroy the existing data?
>
> Is there free software that can write zeroes or some form of nonsense to 
> every storage location?
>
> Thanks
>
> Bob Cochran

As many others have said, the answer is no.

Use the various tools to erase the drive as suggested.

I have actually formatted a drive as VFAT and EXT3 and still recovered 
data off of that drive.  It was not a test but a major mistake on my 
part.  Even recovered data from a drive that was part of an LVM and 
reformatted.

If the drive is small, it may be better to just destroy the drive.  One 
technique that I read about was to drill holes into the drive and fill 
it with Cola.  The acid will destroy the surface of the drive.

I physically take the drives apart and use the platter for various 
things.  They are so shiny at first.  :)

[Srdan Tosovic]

On Thu, 28 May 2009 22:29:23 -0400
Robert L Cochran  wrote:
> I have a hard drive that I need to destroy the data on. What is the
> most dependable way to do this? Can reformatting the drive as ext3 or
> ext4 or some other filesystem effectively destroy the existing data?
>
> Is there free software that can write zeroes or some form of nonsense
> to every storage location?

'shred' is part of coreutils (i.e. installed by default).
Doing something like

shred /dev/sdX

as root will write various bit patterns 25 times over the entire drive
(see the man page for more options).

Srdan

[Bruno Wolff III]

On Fri, May 29, 2009 at 21:51:57 +0200,
  Srdan Tosovic  wrote:
> as root will write various bit patterns 25 times over the entire drive
> (see the man page for more options).

If recovery after one pass of rewriting a disk is a credible threat you
should be physically destroying the disks. Writing over the disk multiple
times is not going to reach some sectors (bad ones or spares) and for most
people the threat of using an electron microscope to try to overwritten data
is not a credible threat. So there isn't a lot of point of doming anything
more than writing zeros over the disk, after the fact. Using block level
encryption in the first place is a relatively cheap way to make recovery
harder as well as protect against some other things.

[Alan Cox]

> 'shred' is part of coreutils (i.e. installed by default).
> Doing something like
>
> shred /dev/sdX
>
> as root will write various bit patterns 25 times over the entire drive
> (see the man page for more options).

Whoopeeedoo. Thats still not the correct way to erase a disk.

Use security erase, that is why it is there.

[Sam Sharpe]

2009/5/29 Alan Cox :
> > 'shred' is part of coreutils (i.e. installed by default).
> > Doing something like
> >
> > shred /dev/sdX
> >
> > as root will write various bit patterns 25 times over the entire drive
> > (see the man page for more options).
>
> Whoopeeedoo. Thats still not the correct way to erase a disk.
>
> Use security erase, that is why it is there.

I use a hammer, because it wins over all other solutions on both ease
of use and catharsis.

[Susi Lehtola]

Quoting "Sharpe, Sam J" :
> 2009/5/29 Alan Cox :
> > > 'shred' is part of coreutils (i.e. installed by default).
> > > Doing something like
> > >
> > > shred /dev/sdX
> > >
> > > as root will write various bit patterns 25 times over the entire drive
> > > (see the man page for more options).
> >
> > Whoopeeedoo. Thats still not the correct way to erase a disk.
> >
> > Use security erase, that is why it is there.
>
> I use a hammer, because it wins over all other solutions on both ease
> of use and catharsis.

For laptop (1.8" and 2.5") disks, sure. A couple of good bangs and you  
have yourself a maraca.

I haven't so far been able to destroy 3.5" disks with a hammer, as the  
enclosure is quite durable. A sledgehammer would probably do the  
trick. Or, you can open up the hard drive and smash the magnetic disks.

[Sam Sharpe]

2009/5/29 Jussi Lehtola :
> Quoting "Sharpe, Sam J" :
> > 2009/5/29 Alan Cox :
> > > > 'shred' is part of coreutils (i.e. installed by default).
> > > > Doing something like
> > > >
> > > > shred /dev/sdX
> > > >
> > > > as root will write various bit patterns 25 times over the entire drive
> > > > (see the man page for more options).
> > >
> > > Whoopeeedoo. Thats still not the correct way to erase a disk.
> > >
> > > Use security erase, that is why it is there.
> >
> > I use a hammer, because it wins over all other solutions on both ease
> > of use and catharsis.
>
> For laptop (1.8" and 2.5") disks, sure. A couple of good bangs and you have
> yourself a maraca.
>
> I haven't so far been able to destroy 3.5" disks with a hammer, as the
> enclosure is quite durable. A sledgehammer would probably do the trick. Or,
> you can open up the hard drive and smash the magnetic disks.

I use some of the undocumented options to /usr/sbin/hammer that are
relevant to larger disks:

hammer --unscrewfirst|-u
       disassemble the drive using a tork wrench first before smashing
the platters
hammer --force|-f
       use more force with the hammer

NOTE: use of -u and -f together is discouraged unless wearing suitable
protective equipment.

[Rick Stevens]

Sharpe, Sam J wrote:
> 2009/5/29 Jussi Lehtola :
> > Quoting "Sharpe, Sam J" :
> > > 2009/5/29 Alan Cox :
> > > > > 'shred' is part of coreutils (i.e. installed by default).
> > > > > Doing something like
> > > > >
> > > > > shred /dev/sdX
> > > > >
> > > > > as root will write various bit patterns 25 times over the entire drive
> > > > > (see the man page for more options).
> > > >
> > > > Whoopeeedoo. Thats still not the correct way to erase a disk.
> > > >
> > > > Use security erase, that is why it is there.
> > >
> > > I use a hammer, because it wins over all other solutions on both ease
> > > of use and catharsis.
> >
> > For laptop (1.8" and 2.5") disks, sure. A couple of good bangs and you have
> > yourself a maraca.
> >
> > I haven't so far been able to destroy 3.5" disks with a hammer, as the
> > enclosure is quite durable. A sledgehammer would probably do the trick. Or,
> > you can open up the hard drive and smash the magnetic disks.
>
> I use some of the undocumented options to /usr/sbin/hammer that are
> relevant to larger disks:
>
> hammer --unscrewfirst|-u
>        disassemble the drive using a tork wrench first before smashing
> the platters
> hammer --force|-f
>        use more force with the hammer
>
> NOTE: use of -u and -f together is discouraged unless wearing suitable
> protective equipment.

I generally take the drives out to the desert and use /sbin/detonate.
As Jamie Hyneman once said on "Mythbusters"...

When in doubt....C4!
----------------------------------------------------------------------
- Rick Stevens, Systems Engineer                      [e-mail] -
- AIM/Skype: therps2        ICQ: 22643734            Yahoo: origrps2 -
-                                                                    -
-         The world is coming to an end ... SAVE YOUR FILES!!!       -
----------------------------------------------------------------------

[Patrick O'Callaghan]

On Fri, 2009-05-29 at 23:37 +0100, Sharpe, Sam J wrote:
> 2009/5/29 Jussi Lehtola :
> > Quoting "Sharpe, Sam J" :
> > > 2009/5/29 Alan Cox :
> > > > > 'shred' is part of coreutils (i.e. installed by default).
> > > > > Doing something like
> > > > >
> > > > > shred /dev/sdX
> > > > >
> > > > > as root will write various bit patterns 25 times over the entire drive
> > > > > (see the man page for more options).
> > > >
> > > > Whoopeeedoo. Thats still not the correct way to erase a disk.
> > > >
> > > > Use security erase, that is why it is there.
> > >
> > > I use a hammer, because it wins over all other solutions on both ease
> > > of use and catharsis.
> >
> > For laptop (1.8" and 2.5") disks, sure. A couple of good bangs and you have
> > yourself a maraca.
> >
> > I haven't so far been able to destroy 3.5" disks with a hammer, as the
> > enclosure is quite durable. A sledgehammer would probably do the trick. Or,
> > you can open up the hard drive and smash the magnetic disks.
>
> I use some of the undocumented options to /usr/sbin/hammer that are
> relevant to larger disks:
>
> hammer --unscrewfirst|-u
>        disassemble the drive using a tork wrench first before smashing
> the platters
> hammer --force|-f
>        use more force with the hammer
>
> NOTE: use of -u and -f together is discouraged unless wearing suitable
> protective equipment.

You're forgetting the -v (verbose) option:

# hammer -v /dev/sda
bang bang bang bang bang bang bang bang bang bang bang bang 
bang bang bang bang bang bang bang bang bang bang bang bang 
bang bang bang bang bang bang bang bang bang bang bang bang 
bang bang bang bang bang bang bang bang bang bang bang bang 
bang bang bang bang bang bang bang bang bang bang bang bang 
...

poc

[Mikkel]

Rick Stevens wrote:
> I generally take the drives out to the desert and use /sbin/detonate.
> As Jamie Hyneman once said on "Mythbusters"...
> When in doubt....C4!

Can I come with the next time you take one out? They will not let me
play with C4 any more. :(

Mike

[Rick Stevens]

Mikkel L. Ellertson wrote:
> Rick Stevens wrote:
> > I generally take the drives out to the desert and use /sbin/detonate.
> > As Jamie Hyneman once said on "Mythbusters"...
> > When in doubt....C4!
>
> Can I come with the next time you take one out? They will not let me
> play with C4 any more. :(

Well, I'm not supposed to either, but "it's only illegal if you get caught!"
> Mike

[Sam Sharpe]

2009/5/30 Mikkel L. Ellertson :
> Rick Stevens wrote:
> > I generally take the drives out to the desert and use /sbin/detonate.
> > As Jamie Hyneman once said on "Mythbusters"...
> >
> > When in doubt....C4!
>
> Can I come with the next time you take one out? They will not let me
> play with C4 any more. :(

I've never been "allowed" to play with explosives (I don't live in the
US). This has not stopped me building up a considerable corpus of
personal knowledge about them. C4 is not a particularly cheap or easy
thing to use - if you want to blow things up, take some lessons from
McVeigh or Kaczynski and use something more common and easy to obtain!

[Sam Sharpe]

2009/5/30 Patrick O'Callaghan :
> On Fri, 2009-05-29 at 23:37 +0100, Sharpe, Sam J wrote:
> > 2009/5/29 Jussi Lehtola :
> > > Quoting "Sharpe, Sam J" :
> > > > 2009/5/29 Alan Cox :
> > > > > > 'shred' is part of coreutils (i.e. installed by default).
> > > > > > Doing something like
> > > > > >
> > > > > > shred /dev/sdX
> > > > > >
> > > > > > as root will write various bit patterns 25 times over the entire drive
> > > > > > (see the man page for more options).
> > > > >
> > > > > Whoopeeedoo. Thats still not the correct way to erase a disk.
> > > > >
> > > > > Use security erase, that is why it is there.
> > > >
> > > > I use a hammer, because it wins over all other solutions on both ease
> > > > of use and catharsis.
> > >
> > > For laptop (1.8" and 2.5") disks, sure. A couple of good bangs and you have
> > > yourself a maraca.
> > >
> > > I haven't so far been able to destroy 3.5" disks with a hammer, as the
> > > enclosure is quite durable. A sledgehammer would probably do the trick. Or,
> > > you can open up the hard drive and smash the magnetic disks.
> >
> > I use some of the undocumented options to /usr/sbin/hammer that are
> > relevant to larger disks:
> >
> > hammer --unscrewfirst|-u
> >        disassemble the drive using a tork wrench first before smashing
> > the platters
> > hammer --force|-f
> >        use more force with the hammer
> >
> > NOTE: use of -u and -f together is discouraged unless wearing suitable
> > protective equipment.
>
> You're forgetting the -v (verbose) option:
>
> # hammer -v /dev/sda
> bang bang bang bang bang bang bang bang bang bang bang bang
> bang bang bang bang bang bang bang bang bang bang bang bang
> bang bang bang bang bang bang bang bang bang bang bang bang
> bang bang bang bang bang bang bang bang bang bang bang bang
> bang bang bang bang bang bang bang bang bang bang bang bang

I was trying to be funny. You succeeded. Well done Sir!

[Robert L Cochran]

On 05/29/2009 05:44 PM, Alan Cox wrote:
> > 'shred' is part of coreutils (i.e. installed by default).
> > Doing something like
> >
> > shred /dev/sdX
> >
> > as root will write various bit patterns 25 times over the entire drive
> > (see the man page for more options).
>
> Whoopeeedoo. Thats still not the correct way to erase a disk.
>
> Use security erase, that is why it is there.

Thanks very much to all who responded! I'm going to use Alan's 
suggestion first of all and if necessary a mixture of everyone else's. 
For good measure maybe I'll dump a pound or so of salt in a gallon of 
nice hot water and drop the hard drive in and wait for signs of rust to 
appear. Ha ha!

Thanks again!

Bob

[g]

Robert L Cochran wrote:
> Thanks very much to all who responded! I'm going to use Alan's 
> suggestion first of all

if you are going to resell drive/system, ok.
> For good measure maybe I'll dump a pound or so of salt in a gallon of 
> nice hot water and drop the hard drive in and wait for signs of rust to 
> appear. Ha ha!

is 'ha ha' because of suggestions, or aluminum rusting?

if you have no need for drive and wish to insure removing all data,
take drive apart, remove disk and burn oxide coating with a torch.
or use lighter fluid or charcoal starter.

[Robert L Cochran]

> is 'ha ha' because of suggestions, or aluminum rusting?

I think the idea of dropping a hard drive in brine is funny. Hence the 
ha ha!
> if you have no need for drive and wish to insure removing all data,
> take drive apart, remove disk and burn oxide coating with a torch.
> or use lighter fluid or charcoal starter.

That's another interesting suggestion. Very imaginative too!

Bob

[g]

Robert L Cochran wrote:
> I think the idea of dropping a hard drive in brine is funny. Hence the 
> ha ha!

ok. be aware that you would have to open cover to allow good saturation of
inner contents. many drives are sealed in such a way that there is little
to no venting. this is to keep moisture out and prevent rust, oxidation
or other corroding of inner surfaces. some have pressure compensation.
> That's another interesting suggestion. Very imaginative too!

it works. but be sure that you do not inhale fumes. iron oxide particles
are not good for lungs.

all in all, it is one of easiest ways insuring that all data is destroyed.

passing a large strong magnet over surfaces is second easiest.

i have used ceramic magnets from speakers. 2 of same size on opposite sides
of disk with poles attracting is very effective. just put something on
surfaces to allow movement of disk.

[Nifty Fedora Mitch]

On Fri, May 29, 2009 at 4:39 AM, Ambrogio  wrote:
> Il giorno ven, 29/05/2009 alle 14.52 +1200, Clint Dilks ha scritto:
> > > dd if=/dev/zero of=/dev/youbettergetthisright bs=1M
> >
> > If you want to be really sure you need to do the command above several
> > time or use software like
> >
> > http://www.dban.org/
>
> /dev/zero is not the right device to use.
> Better is /dev/random or /dev/urandom
> But they are not speed

See the mkfs.ext3 man page for:
  "-c
  "    Check the device for bad blocks before creating the file
system. If this option is
       specified twice, then a slower, read-write test is used instead
of a fast read-only test. "

Once the device is formatted the paranoid can fill it with files
containing random
and other bit patterns (0xa5a5, 0x5a5a, 0x0000, 0xFFFF..).

Solve the dev/random dev/urandom slow part by reusing a modest block of
random bits over and over to build large and small files that fill  the disk.
Finish with lots of copies of your favorite Fedora.iso image file.

The cautious should use vendor tools to reformat the disk...
Special attention to the partition table should be given so 'spare'
or 'hidden' partitions are dealt with.

The very very paranoid should cut the drive into bits with a cutting torch
since bad block spares or unused flash ram might contain sequestered
bits that might  get recovered.

[Tim]

On Fri, 2009-05-29 at 13:31 +0100, Alan Cox wrote:
> It makes no real difference - use the drives own secure erase feature if
> you want to be sure, otherwise you've got no guarantee that everything
> will be cleared - only the drive knows enough to do the job.

But do you know what the drive does when you use that function?  ;-\

[mike cloaked]

Alan Cox wrote:
> Use security erase, that is why it is there.

How do you access the security erase facility?

[Robert L Cochran]

On 05/30/2009 04:49 AM, Mike Cloaked wrote:
> Alan Cox wrote:
> > Use security erase, that is why it is there.
>
> How do you access the security erase facility?

From `man hdparm`:

--security-erase PWD
Erase (locked) drive, using password PWD (DANGEROUS). Password is given 
as an ASCII string and is padded with NULs to reach 32 bytes. The
applicable drive password is selected with the --user-master switch. No 
other flags are permitted on the command line with this one. THIS FEA-
TURE IS EXPERIMENTAL AND NOT WELL TESTED. USE AT YOUR OWN RISK.

--security-erase-enhanced PWD
Enhanced erase (locked) drive, using password PWD (DANGEROUS). Password 
is given as an ASCII string and is padded with NULs to reach 32 bytes.
The applicable drive password is selected with the --user-master switch. 
No other flags are permitted on the command line with this one. THIS
FEATURE IS EXPERIMENTAL AND NOT WELL TESTED. USE AT YOUR OWN RISK.

I think that is what Alan means. You can google on 'security erase' to 
look for the procedure for doing it. The drive itself has to be capable 
of this kind of erasure.

Bob

[Bruno Wolff III]

On Sat, May 30, 2009 at 18:16:00 +0930,
  Tim  wrote:
> On Fri, 2009-05-29 at 13:31 +0100, Alan Cox wrote:
> > It makes no real difference - use the drives own secure erase feature if
> > you want to be sure, otherwise you've got no guarantee that everything
> > will be cleared - only the drive knows enough to do the job.
>
> But do you know what the drive does when you use that function?  ;-\

Reading the drive back in should give you a good idea. If that isn't enough
of a check for you then you should just be destroying the drive.

[Beartooth]

On Fri, 29 May 2009 16:57:09 -0700, Rick Stevens wrote:
> Mikkel L. Ellertson wrote:
> > Rick Stevens wrote:
> > > I generally take the drives out to the desert and use /sbin/detonate.
> > > As Jamie Hyneman once said on "Mythbusters"...
> > > When in doubt....C4!
> >
> > Can I come with the next time you take one out? They will not let me
> > play with C4 any more. :(
>
> Well, I'm not supposed to either, but "it's only illegal if you get
> caught!"

I have it on excellent authority that a .45 acp won't make a hole 
clear through a hard drive, but that a .30-06 will.

[Mikkel]

Sharpe, Sam J wrote:
> 2009/5/30 Mikkel L. Ellertson :
> > Rick Stevens wrote:
> > > I generally take the drives out to the desert and use /sbin/detonate.
> > > As Jamie Hyneman once said on "Mythbusters"...
> > > When in doubt....C4!
> >
> > Can I come with the next time you take one out? They will not let me
> > play with C4 any more. :(
>
> I've never been "allowed" to play with explosives (I don't live in the
> US). This has not stopped me building up a considerable corpus of
> personal knowledge about them. C4 is not a particularly cheap or easy
> thing to use - if you want to blow things up, take some lessons from
> McVeigh or Kaczynski and use something more common and easy to obtain!

This should probably be taken to another list... But I can not
resist one last comment - low explosives like McVeigh was reported
to have used would probably send the drive flying, rather then
destroying it directly. A shaped charge from C4 will tend to shatter
the drive. You could also use thermite (sp) to melt the drive.

Now, if I have a bunch of drives to erase, I would probably ask
Steve to let me barrow the induction furnace. Between the magnetic
field, and the fact that they would become a puddle, I don't think
any data could be recovered. It would add a few impurities to the
mix, so it probably would have to go in with a load of scrap.

Mike

[SternData]

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Hash: SHA1

On 05/29/2009 10:08 AM, Robin Laing wrote:
> Robert L Cochran wrote:
> > I have a hard drive that I need to destroy the data on. What is the
> > most dependable way to do this? Can reformatting the drive as ext3 or
> > ext4 or some other filesystem effectively destroy the existing data?
> >
> > Is there free software that can write zeroes or some form of nonsense
> > to every storage location?
> >
> > Thanks
> >
> > Bob Cochran
>
> As many others have said, the answer is no.
>
> Use the various tools to erase the drive as suggested.
>
> I have actually formatted a drive as VFAT and EXT3 and still recovered
> data off of that drive.  It was not a test but a major mistake on my
> part.  Even recovered data from a drive that was part of an LVM and
> reformatted.
>
> If the drive is small, it may be better to just destroy the drive.  One
> technique that I read about was to drill holes into the drive and fill
> it with Cola.  The acid will destroy the surface of the drive.
>
> I physically take the drives apart and use the platter for various
> things.  They are so shiny at first.  :)

I like to put the drives on a sidewalk and whack them a few times with
an 8 lb sledge hammer.  When I pick up the drive and shake it and it
makes a nice jingling sound, the job is done.

- --

Steve
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[Wolfgang S. Rupprecht]

"Mikkel L. Ellertson"  writes:
> This should probably be taken to another list... But I can not
> resist one last comment - low explosives like McVeigh was reported
> to have used would probably send the drive flying, rather then
> destroying it directly. A shaped charge from C4 will tend to shatter
> the drive. You could also use thermite (sp) to melt the drive.

McVeigh used ANFO, a common and cheap high explosive used for road work,
by farmers to remove boulders etc.  The wiki article does claim the
propagation velocity of the explosion is faster than the speed of sound.
That would make it a high explosive.

http://en.wikipedia.org/wiki/ANFO

As for decommissioning a drive with secrets on it, I have no idea if it
is a good choice.  dd-ing /dev/zero over the raw partition works well
enough for me, but then I don't need to clear my drives in only a few
milliseconds.

-wolfgang

[Jonathan Ryshpan]

> On 05/30/2009 04:49 AM, Mike Cloaked wrote:
> How do you access the security erase facility?

All kidding aside, there's a web site from which you can download a
little DOS utility to invoke security erase on a drive.  The README
claims that security erase is better than smashing the drive to bits,
though (I suspect) not better then pulling out the platters and
blowtorching them till the oxide falls off.

URL for the site is:
        http://cmrr.ucsd.edu/people/Hughes/SecureErase.shtml

jon

[Nifty Fedora Mitch]

On Mon, Jun 01, 2009 at 01:58:27AM -0700, Jonathan Ryshpan wrote:
> > On 05/30/2009 04:49 AM, Mike Cloaked wrote:
> > How do you access the security erase facility?
>
> All kidding aside, there's a web site from which you can download a
> little DOS utility to invoke security erase on a drive.  The README
> claims that security erase is better than smashing the drive to bits,
> though (I suspect) not better then pulling out the platters and
> blowtorching them till the oxide falls off.
>
> URL for the site is:
>         http://cmrr.ucsd.edu/people/Hughes/SecureErase.shtml

Use disk vendor tools!

If you are an individual worried about other individuals 
reading your data then vendor tools are more than enough.

Each vendor has their own download tool set to partition, format and
check the drive for errors. Look for (demand) tools you can burn
to a stand alone CDROM.... (think .iso file).

These tools are most valueable when repurposing hardware inside
an organization.

Speaking of Burn.... the only way to 100% wipe a magnetic drive 
is to take the media up to and beyond the Curie point -- i.e. 
blow torch to cut it in half...  turn it to slag.

http://en.wikipedia.org/wiki/Curie_point

If you are an "agency" then you should not be getting info from this list
so go away or call me for an expensive consultation gig.   Governments
will go to astounding lengths to extract data each group has policy and
procedures to match the needs.

If you are a company (federal contract, human resources personal data,
credit card data or pharmaceutical company for example) then each drive
and the data set needs to be tracked and audited from beginning to end
and more.   By more I mean that it is important to comply with national, state and
local policy and regulations.   Any ad-hock tool is fine and dandy but will not
meet compliance requirements unless it happens to be specified.

If you are a criminal just toss it in the dumpster no one will
find it anyhow.

Following Jonathan's excelent URL pointer found this fun read:

http://cmrr.ucsd.edu/people/Hughes/DataSanitizationTutorial.pdf

[Tim]

On Sun, 2009-05-31 at 12:52 -0500, Steven Stern wrote:
> I like to put the drives on a sidewalk and whack them a few times with
> an 8 lb sledge hammer.  When I pick up the drive and shake it and it
> makes a nice jingling sound, the job is done.

Wouldn't you love to see someone doing that out the front of a computer
shop, just as some customers were about to come in to get their PC
fixed?   ;-)  You could imagine them turning around and walking away as
fast as they could manage.

[Tim]

Tim:
> > But do you know what the drive does when you use that function?  ;-\

Bruno Wolff III:
> Reading the drive back in should give you a good idea. If that isn't enough
> of a check for you then you should just be destroying the drive.

While that would tell you that *you* couldn't read your own drive back,
it doesn't tell you whether someone else could.  In the paranoid
security concious arena, you'd need to know exactly how their secure
erase function works, before you could trust it.

[Tim]

On Mon, 2009-06-01 at 01:58 -0700, Jonathan Ryshpan wrote:
> The README claims that security erase is better than smashing the
> drive to bits, though (I suspect) not better then pulling out the
> platters and blowtorching them till the oxide falls off.

Though not as fun...

[Robert L Cochran]

On 05/29/2009 09:46 PM, Robert L Cochran wrote:
> On 05/29/2009 05:44 PM, Alan Cox wrote:
> > > 'shred' is part of coreutils (i.e. installed by default).
> > > Doing something like
> > >
> > > shred /dev/sdX
> > >
> > > as root will write various bit patterns 25 times over the entire drive
> > > (see the man page for more options).
> >
> > Whoopeeedoo. Thats still not the correct way to erase a disk.
> >
> > Use security erase, that is why it is there.
>
> Thanks very much to all who responded! I'm going to use Alan's 
> suggestion first of all and if necessary a mixture of everyone else's. 
> For good measure maybe I'll dump a pound or so of salt in a gallon of 
> nice hot water and drop the hard drive in and wait for signs of rust 
> to appear. Ha ha!
>
> Thanks again!
>
> Bob

I bet you all want to know what I did to the hard drive. Well, maybe you 
don't. First off, I tried to find out of the drive has a secure erase 
feature.

# hdparm -I /dev/sdb

/dev/sdb:
HDIO_DRIVE_CMD(identify) failed: Invalid exchange
# hdparm -i /dev/sdb

/dev/sdb:
HDIO_GET_IDENTITY failed: Invalid argument

[It does not seem to have a secure erase feature.]

[So I did this:]

# dd if=/dev/zero of=/dev/sdb bs=1M
dd: writing `/dev/sdb': No space left on device
28630+0 records in
28629+0 records out
30020272128 bytes (30 GB) copied, 1579.48 s, 19.0 MB/s
#

...and tomorrow, I will remove the circuit board from the drive, and if 
time allows, try out the brine-and-cola treatment. Or perhaps I'll 
disassemble the drive into parts for my own education.

Thanks everyone!

Bob

[Mike McCarty]

Robert L Cochran wrote:
> I have a hard drive that I need to destroy the data on. What is the most 
> dependable way to do this? Can reformatting the drive as ext3 or ext4 or 
> some other filesystem effectively destroy the existing data?
>
> Is there free software that can write zeroes or some form of nonsense to 
> every storage location?

Overwriting the disc, even several times, is not enough to guarantee
that the data _cannot_ be recovered. If you truly need to make the
data unrecoverable, then a hammer is all that's needed. To be truly
sure, open the case (also requires a screwdriver or nutdriver),
and shatter each disc separately. They are usually ceramic these
days, I think. Anyway, physical destruction is the only real guarantee.

Mike

[Fernando Cassia]

On Tue, Jun 9, 2009 at 6:00 PM, Mike McCarty wrote:
> Robert L Cochran wrote:
> > I have a hard drive that I need to destroy the data on. What is the most
> > dependable way to do this? Can reformatting the drive as ext3 or ext4 or
> > some other filesystem effectively destroy the existing data?
> >
> > Is there free software that can write zeroes or some form of nonsense to
> > every storage location?

I haven´t done this task from Linux, but if you´ve got access to a windows
computer (or VM)  and you can install the drive into an external USB
enclosure, use this GPL program
http://sourceforge.net/projects/eraser/

FC

[Henrik Schmiediche]

Check out:

http://www.dban.org

-          Henrik

From: [e-mail] [mailto:[e-mail]]
On Behalf Of Fernando Cassia
Sent: Wednesday, June 10, 2009 2:51 PM
To: Community assistance, encouragement, and advice for using Fedora.
Subject: Re: OT: Can Reformatting A Hard Drive To ext3 Destroy All the Data
On It?

On Tue, Jun 9, 2009 at 6:00 PM, Mike McCarty 
wrote:

Robert L Cochran wrote:

I have a hard drive that I need to destroy the data on. What is the most
dependable way to do this? Can reformatting the drive as ext3 or ext4 or
some other filesystem effectively destroy the existing data?

Is there free software that can write zeroes or some form of nonsense to
every storage location?

I haven´t done this task from Linux, but if you´ve got access to a windows
computer (or VM)  and you can install the drive into an external USB
enclosure, use this GPL program
http://sourceforge.net/projects/eraser/

FC

[Rick Stevens]

Henrik Schmiediche wrote:
> Check out:
>
> http://www.dban.org
>      Henrik
>
>
>
> From: [e-mail] [mailto:[e-mail]]
> On Behalf Of Fernando Cassia
> Sent: Wednesday, June 10, 2009 2:51 PM
> To: Community assistance, encouragement, and advice for using Fedora.
> Subject: Re: OT: Can Reformatting A Hard Drive To ext3 Destroy All the Data
> On It?
>
> On Tue, Jun 9, 2009 at 6:00 PM, Mike McCarty 
> wrote:
>
> Robert L Cochran wrote:
>
> I have a hard drive that I need to destroy the data on. What is the most
> dependable way to do this? Can reformatting the drive as ext3 or ext4 or
> some other filesystem effectively destroy the existing data?
>
> Is there free software that can write zeroes or some form of nonsense to
> every storage location?

shred (man shred) will do it.  "dd if=/dev/zero of=/dev/sda" would do
it.  Not that none of these guarantee that a disk will be unreadable.
Not even commercial programs.

No matter how many times you rewrite the media, someone with equipment
sophisticated enough may be able to read the data.  The only way to
ensure that a drive is unreadable is to physically destroy the platters.
Scraping off the magnetic coating into a fine dust is probably the
best...it would be possible, given enough time, to reconstruct a
shattered platter.
> I haven´t done this task from Linux, but if you´ve got access to a windows
> computer (or VM)  and you can install the drive into an external USB
> enclosure, use this GPL program
> http://sourceforge.net/projects/eraser/
>
> FC

[Robert L Cochran]

I'm surprised this thread was reawakened...makes me wonder what sort of 
child I created here!

I first used Alan's suggestion about checking for, and if possible, 
using the security erase feature of a security-erase enabled hard drive. 
This drive was too old to have such a feature. I checked it with hdparm 
-I and then hdparm -i to verify the fact.

I then used Sam's dd suggestion on the drive. I selected his suggestion 
because dd is standard Unix/Linux software, it has presumably passed 
security audits, and I don't have to make some decision about whether it 
would "phone home" on me or perhaps leave a nice little tar file on some 
area of the drive.

Then I disassembled the drive. You don't need a standard screwdriver for 
it; the main requirement is a torx driver and a little ability to peel 
off the seals marked "warranty void if removed".

I then did some fairly nasty things to the read/write heads and platters 
and threw out certain items drive hardware so that it is most unlikely 
the drive can be reassembled. The platters were futher belabored and 
rendered scratched, badly bent, and little-kid dirty.

Thanks to all who answered. I'm anxious to try out Alan's "security 
erase" suggestion on a much newer drive. It appears to be a lot less 
labor intensive.

Bob

On 06/09/2009 05:00 PM, Mike McCarty wrote:
> Robert L Cochran wrote:
> > I have a hard drive that I need to destroy the data on. What is the 
> > most dependable way to do this? Can reformatting the drive as ext3 or 
> > ext4 or some other filesystem effectively destroy the existing data?
> >
> > Is there free software that can write zeroes or some form of nonsense 
> > to every storage location?
>
> Overwriting the disc, even several times, is not enough to guarantee
> that the data _cannot_ be recovered. If you truly need to make the
> data unrecoverable, then a hammer is all that's needed. To be truly
> sure, open the case (also requires a screwdriver or nutdriver),
> and shatter each disc separately. They are usually ceramic these
> days, I think. Anyway, physical destruction is the only real guarantee.
>
> Mike

[Fernando Cassia]

On Wed, Jun 10, 2009 at 5:49 PM, Robert L Cochran wrote:
> I'm surprised this thread was reawakened...makes me wonder what sort of
> child I created here!
>
> I first used Alan's suggestion about checking for, and if possible, using
> the security erase feature of a security-erase enabled hard drive. This
> drive was too old to have such a feature. I checked it with hdparm -I and
> then hdparm -i to verify the fact.
>
> I then used Sam's dd suggestion on the drive. I selected his suggestion
> because dd is standard Unix/Linux software, it has presumably passed
> security audits, and I don't have to make some decision about whether it
> would "phone home" on me or perhaps leave a nice little tar file on some
> area of the drive.
>
> Then I disassembled the drive. You don't need a standard screwdriver for it;
> the main requirement is a torx driver and a little ability to peel off the
> seals marked "warranty void if removed".
>
> I then did some fairly nasty things to the read/write heads and platters and
> threw out certain items drive hardware so that it is most unlikely the drive
> can be reassembled. The platters were futher belabored and rendered
> scratched, badly bent, and little-kid dirty

With all that effort to securely erase the data, and the question on a
public mailing ist, anybody would think that you HAD important data to
begin with in there!.

If I were an evildoer, I´d google your name, lookup your home address
and then pick up your trash tonight.
*VBG*

FC

[James Kosin]

Tim wrote:
> Tim:
> > > But do you know what the drive does when you use that function?  ;-\
>
> Bruno Wolff III:
> > Reading the drive back in should give you a good idea. If that isn't enough
> > of a check for you then you should just be destroying the drive.
>
> While that would tell you that *you* couldn't read your own drive back,
> it doesn't tell you whether someone else could.  In the paranoid
> security concious arena, you'd need to know exactly how their secure
> erase function works, before you could trust it.

Unfortunately, the only way to guarantee complete security is to
completely destroy the drive.

Writing 0-zeros or other data may still leave ghost trails a really good
expert (say with government connections and the proper hardware) could
still read back.

James

[Robin Laing]

Rick Stevens wrote:
> Henrik Schmiediche wrote:
> > Check out:
> >
> > http://www.dban.org
> >      Henrik
> >
> >
> >
> > From: [e-mail] 
> > [mailto:[e-mail]]
> > On Behalf Of Fernando Cassia
> > Sent: Wednesday, June 10, 2009 2:51 PM
> > To: Community assistance, encouragement, and advice for using Fedora.
> > Subject: Re: OT: Can Reformatting A Hard Drive To ext3 Destroy All the 
> > Data
> > On It?
> >
> > On Tue, Jun 9, 2009 at 6:00 PM, Mike McCarty 
> > wrote:
> >
> > Robert L Cochran wrote:
> >
> > I have a hard drive that I need to destroy the data on. What is the most
> > dependable way to do this? Can reformatting the drive as ext3 or ext4 or
> > some other filesystem effectively destroy the existing data?
> >
> > Is there free software that can write zeroes or some form of nonsense to
> > every storage location?
>
> shred (man shred) will do it.  "dd if=/dev/zero of=/dev/sda" would do
> it.  Not that none of these guarantee that a disk will be unreadable.
> Not even commercial programs.
>
> No matter how many times you rewrite the media, someone with equipment
> sophisticated enough may be able to read the data.  The only way to
> ensure that a drive is unreadable is to physically destroy the platters.
> Scraping off the magnetic coating into a fine dust is probably the
> best...it would be possible, given enough time, to reconstruct a
> shattered platter.

But the point is how much does someone want to spend to recover the 
data.  If you don't have state secrets where noone else has backups, 
then I really doubt anyone will invest the time and money to recover the 
data.

There was a challenge put out to recover data that was erased with dd 
but no takers.  The comment that I read on the web site pointed to a 
phone call that dd makes it to costly to recover.

[Susi Lehtola]

On Thu, 2009-06-11 at 10:38 -0600, Robin Laing wrote:
> There was a challenge put out to recover data that was erased with dd 
> but no takers.  The comment that I read on the web site pointed to a 
> phone call that dd makes it to costly to recover.

The title says it all:

http://www.h-online.com/news/Secure-deletion-a-single-overwrite-will-do-it--...

A few excerpts:

"Craig Wright, a forensics expert, claims to have put this legend
finally to rest. He and his colleagues ran a scientific study to take a
close look at hard disks of various makes and different ages,
overwriting their data under controlled conditions and then examining
the magnetic surfaces with a magnetic-force microscope. They presented
their paper at ICISS 2008 and it has been published by Springer AG in
its Lecture Notes in Computer Science series (Craig Wright, Dave
Kleiman, Shyaam Sundhar R. S.: Overwriting Hard Drive Data: The Great
Wiping Controversy)."

"A single bit whose precise location is known can in fact be correctly
reconstructed with 56 per cent probability (in one of the quoted
examples). To recover a byte, however, correct head positioning would
have to be precisely repeated eight times, and the probability of that
is only 0.97 per cent. Recovering anything beyond a single byte is even
less likely."

[g]

Beartooth wrote:
> I have it on excellent authority that a .45 acp won't make a hole
> clear through a hard drive, but that a .30-06 will.

factory .45 acp may not. custom .45 acp can.

.357 mag good for spindle  motor.

rem 720 .306 can at 600 yds. .25c print @ 100 yds

[Bruno Wolff III]

On Wed, Jun 10, 2009 at 16:49:03 -0400,
  Robert L Cochran  wrote:
> Thanks to all who answered. I'm anxious to try out Alan's "security  
> erase" suggestion on a much newer drive. It appears to be a lot less  
> labor intensive.

If you are really worried about this, set up encrypted partitions when
you install on the new drive, so the unencrypted bits (other than stuff
in /boot) never get to the drive in the first place.