getting rid of a hard drive? shred it!

[splat]

I'm sure all of you already do this (because you are all smart, right :) ), but I figured it was worth passing along this tip once again. If you are selling, throwing away, or giving away a hard drive, protect yourself form prying eyes. Formatting is not enough, you must overwrite the data on the disk. An easy way to do this is to download a live Linux cd, like Knoppix (http://www.knoppix.org) and use 'shred' to get rid of all the data on the disk.

example:# shred -z -v /dev/hda
this will overwrite the disk the default 25 times, then it will fill the entire disk with 0's. The -v option is "verbose" so you can see what's going on.

here is the man page for more info: http://linux.die.net/man/1/shred

[nd4spdbh2]

I'm sure all of you already do this (because you are all smart, right :) ), but I figured it was worth passing along this tip once again. If you are selling, throwing away, or giving away a hard drive, protect yourself form prying eyes. Formatting is not enough, you must overwrite the data on the disk. An easy way to do this is to download a live Linux cd, like Knoppix (http://www.knoppix.org) and use 'shred' to get rid of all the data on the disk.

example:# shred -z -v /dev/hda
this will overwrite the disk the default 25 times, then it will fill the entire disk with 0's. The -v option is "verbose" so you can see what's going on.

here is the man page for more info: http://linux.die.net/man/1/shred


ieesh 25 passes of 0's that would take FOREVER! lol but it definetly would be secure.

[thideras]

ieesh 25 passes of 0's that would take FOREVER! lol but it definetly would be secure.It doesn't do 25 passes of zero's. That is actually still pretty easy to recover data from.

It does a series of different patterns with some "random" overwrites across the entire disk. Then I believe the last 3 passes writes zeros. :D

There is a name for that series of overwrites, but I forgot it >.<

[torin3]

ieesh 25 passes of 0's that would take FOREVER! lol but it definetly would be secure.

Maybe not more than 3 writes of random data would be:

http://www.ocforums.com/showthread.php?t=541814

[splat]

ieesh 25 passes of 0's that would take FOREVER! lol but it definetly would be secure.

its 25 passes of random data. i've seen a few places that say shred actually has 25 set algorithms that it uses, so 25 passes uses all of those. you can use the -n option to set a smaller number of iterations if you aren't as paranoid or don't have as much time. the -z options does one more pass of all 0's.

[CGR]

Pfft... Here is the real way to shred a drive:

http://www.youtube.com/watch?v=sQYPCPB1g3o&e

:)

[nd4spdbh2]

Pfft... Here is the real way to shred a drive:

http://www.youtube.com/watch?v=sQYPCPB1g3o&e

:)

NOW we are talking shred!

[gangaskan]

that thing can sure shred but ... will it blend? :P

[Hookem]

Hummm...I just use Deriks Boot and Nuke.

Supposed to work.

Any comments ???

[conway]

Hummm...I just use Deriks Boot and Nuke.

Supposed to work.

Any comments ???

I use dban myself, or Acronis Drive Cleanser from within Windows.

[thegreek]

DBAN 35-pass Gutmann (if you want really secure)

within windows use Eraser - http://sourceforge.net/projects/eraser/

[hafa]

Pfft... Here is the real way to shred a drive:

http://www.youtube.com/watch?v=sQYPCPB1g3o&e

:)

Man, I want one! My only question is: why does he just feed in one drive at a time? That thing looks capable of doing the entire box at a run!

Thanks for the OP, splat. Definitely more thorough than the OEM zero write utilities out there.

[Neuromancer]

Pfft... Here is the real way to shred a drive:

http://www.youtube.com/watch?v=sQYPCPB1g3o&e

:)

Actually data can still be recovered from them believe it or not. In the military we are taught that in a pinch that is the fastest method of destruction (ship is being overrun etc) however... best method is overwrites and then physical destruction of the disk.

And that 25 times etc.. I have been through this before and heard that DoD standards is 99 wipes, but I read that on the internet. I could have sworn that the software we used was much lower. But hdds that contain secret material are never used, so maybe 3-6 wipes and then physical destruction is enough.

[Adragontattoo]

A blow torch melting the platters will render it impossible to recover the data no matter what you run.

[hafa]

Actually data can still be recovered from them believe it or not...

I think I'll choose not to, thank you. IMHO, there's simply no way you're getting any useful data from a tiny bit of a physically shredded platter the largest piece of which is < 1cm.

[Drew@PSU]

While I have to agree with hafa, destruction of secret drives ( army standard ) is crazy. 25 passes I believe is the overwrite section, degaussing ( big magnet ) then it gets burned/shredded. IIRC, they have a smaller version of that shredder in electronic warfare aircraft. I think we actually had a conversation about the best way to get rid of data on a drive, something like this....check that, its the infamous kill button thread, here (http://www.ocforums.com/showthread.php?t=157930).

Back on topic, the OP is right, too many people don't do ANYTHING to their HDDs before they get rid of it. The live CD is a great idea since it doesn't require anything to be installed, since that will undoubtedly be erased during the whole process anyway.

[gangaskan]

While I have to agree with hafa, destruction of secret drives ( army standard ) is crazy. 25 passes I believe is the overwrite section, degaussing ( big magnet ) then it gets burned/shredded. IIRC, they have a smaller version of that shredder in electronic warfare aircraft. I think we actually had a conversation about the best way to get rid of data on a drive, something like this....check that, its the infamous kill button thread, here (http://www.ocforums.com/showthread.php?t=157930).



at work we normally hold them for our evidence guy in the police department and he throws them into the steel mill, tends to do the trick :)

[MoPMatrix]

When selling a drive I use dban
When throwing 1 out I use a drill press and the biggest bit I have =)

[Audioaficionado]

I rip 'em apart and make wind chimes out of the platters.

[EmAn]

I shoot them with a potato cannon or high powered rifle :)

[Hookem]

Wow...I guess I live a boring life...I could sell one of my hard drives and I cant think of one thing on my computers that anybody would be even remotely interested in.

I personally could care less if someone got one of my hard drives and got every single thing I ever had on it, off of it.

Oh well...Guess I will never qualify for a "double knot spy"...In the immortal words of Jethro Bodine.

[MadMan007]

Wow...I guess I live a boring life...I could sell one of my hard drives and I cant think of one thing on my computers that anybody would be even remotely interested in.

I personally could care less if someone got one of my hard drives and got every single thing I ever had on it, off of it.

Oh well...Guess I will never qualify for a "double knot spy"...In the immortal words of Jethro Bodine.

If you do anything financial on your computer I'd rethink that outlook. I'm not overly paranoid but I do keep my active computer clean and I data wipe any HD I sell.

[MoPMatrix]

Wow...I guess I live a boring life...I could sell one of my hard drives and I cant think of one thing on my computers that anybody would be even remotely interested in.

I personally could care less if someone got one of my hard drives and got every single thing I ever had on it, off of it.

Oh well...Guess I will never qualify for a "double knot spy"...In the immortal words of Jethro Bodine.


Hope u don't auto save any of ur passwords.

I've have had multiple PCs that I bought, people gave to me or found in the trash.
I could sign onto their AIM accounts, check their email, post on the forums they visit.
One PC someone gave me had a retail site password saved and their CC saved in their account. I could of bought stuff if I wanted to.
I dban'd the PC and sold it.

Theres a lot more in there then u think.

[Hookem]

After being told right here at overclockers forums not to auto save any passwords ever...Well I dont do all that business.

I have no finacial information on my computer...I do not pay my bills online...I rarely if ever use credit cards online...PayPal broke me of all that business.

I do not have any "contact" information in Outlook...Guess being in my 50's I like doing things the old fashion way.

Hell it is hard enough fighting off the identity thieves...I am sure not going to have banking and personal finaical information on my computers.

So what is the deal??? Is Derik's Boot and Nuke sufficent or not ???

[hkgonra]

I can't believe nobody has linked to this thread yet.

http://www.ocforums.com/showthread.php?t=396441

[splat]

After being told right here at overclockers forums not to auto save any passwords ever...Well I dont do all that business.

I have no finacial information on my computer...I do not pay my bills online...I rarely if ever use credit cards online...PayPal broke me of all that business.

I do not have any "contact" information in Outlook...Guess being in my 50's I like doing things the old fashion way.

Hell it is hard enough fighting off the identity thieves...I am sure not going to have banking and personal finaical information on my computers.

So what is the deal??? Is Derik's Boot and Nuke sufficent or not ???

wouldn't you rather KNOW that there is nothing on there? That's the whole point here. Wouldn't you rather take the extra 10 minutes or even 30 minutes to run 2 or 3 iterations of random data to protect yourself just in case there happens to be something on there? Better safe than sorry, right?

[Hookem]

wouldn't you rather KNOW that there is nothing on there? That's the whole point here. Wouldn't you rather take the extra 10 minutes or even 30 minutes to run 2 or 3 iterations of random data to protect yourself just in case there happens to be something on there? Better safe than sorry, right?

I am safe if Boot and Nuke works...I always do the autonuke and man 30 minutes would have me dancing in the streets.

500 gig hard drives take forever...At least 5 or 6 hours...Sometimes longer.

:bang head

I like the Acronis Drive Cleanser also...I do alot of data recovery and it is nice to just plug the drive in one of my computers and let er rip after recovering the data right there in windows...Great program IMHO...Of course !!!!

:burn:

[Archer36]

example:# shred -z -v /dev/hda
this will overwrite the disk the default 25 times, then it will fill the entire disk with 0's. The -v option is "verbose" so you can see what's going on.

here is the man page for more info: http://linux.die.net/man/1/shred
Been there done that, but my target drive was /dev/sda to nuke my thumb drive. However a typo I put in /dev/hda, it was gone all of it before I noticed about half way through. :beer:

So double check everything you type!

[iansmith]

A simple one-pass wipe of the drive will be good enough to protect against anyone not willing to spend ten grand or more to try and recover data off the drive.

If you have data worth more than for someone to recover on your computer, what the hell are you doing selling old drives for spare change anyways? :-)

And actually, I'm not sure how much is possible to recover off a drive wiped once or twice. Hard drive density and technology has been increasing fast, as well as the complexity of how the data is actually written. All the stories of how wiped drives can be recovered are like ten years old.. if it is even possible to do it to a modern drive, it might cost way more than anyone is going to spend to try and get your myspace passwords.

But if you have the time to spend wiping, go ahead... I suppose it's better to be too paranoid than not enough.

[videobruce]

Ok, magnetic media questions;

1. Erasing removes what percentage of the existing magnetic pattern (data)?
2. You erase a video tape, the old recodring is gone. You erase a audio tape, it's pretty much gone. Is it because of the fact the data is so close togetrher, the erasing process has to be limited regarding strength of the magnetic field?
3. What type of programs can extract data that have been erased, or better yet written over with zeros?
4. Has anyone used a video tape bulk eraser (not one of those cheap 1/2" consumer models, but one for at least 3/4" tape) and if so the results?

[iansmith]

When you erase magnetic media in it's intended device such as a consumer vcr, tape drive or hard drive there is no software that can recover it. When you think about it, nobody wants to see ghost images of a previous recording on a erased tape, and nobody wants old files to start mixing in with current files on their hard drive. So the devices make sure to wipe them out to the point where they can't detect them anymore.

What can be done is to build special hardware that can scan the media at extreme resolutions and sensitivity, far beyond what the consumer device is capable of, and from there try and reconstruct the data with programs written with the understanding of how the magnetic information is changed when being overwritten, a very complex process.

So if you format a drive, or erase a videotape there is no way to recover either of them without some very expensive hardware. In the case of the hard drive, this means taking it apart and mounting the platters one by one to be scanned slowly.

A bulk eraser does a good job on audo and video tapes, enough that you can't recover it with standard equipment.

It wouldn't do any good on a hard drive, the metal enclosure protects it from most magnetic fields.

[Mr.Guvernment]

I think I'll choose not to, thank you. IMHO, there's simply no way you're getting any useful data from a tiny bit of a physically shredded platter the largest piece of which is < 1cm.

how do you know, it could be very easy for them to get a small sector that would contain an entire say txt file or document or image placed on that section of the HD....

[iansmith]

Hard drives write to all the platters at the same time, so they would be missing some of the bits from each byte of the file they recovered.

But a better idea than shredding is to sandpaper the platters to remove the magnetic coating. No way that can be recoverable! No idea what the coating is made of, so as the Blend It guy says, "Don't breathe that!"

[WiSH2oo0]

Now that I picked up my new WD VR 300GB HDD. I'm going to be selling my old hard drives. Is this Knoppix program still the best way to erase data off my old HDD?

[thideras]

Now that I picked up my new WD VR 300GB HDD. I'm going to be selling my old hard drives. Is this Knoppix program still the best way to erase data off my old HDD?I personally use Darin's Boot and Nuke (DBAN). Works VERY well.

[MadMan007]

DBAN 35-pass Gutmann (if you want really secure)

within windows use Eraser - http://sourceforge.net/projects/eraser/

Is that comparable to DBan? I use a DBan CD now and even though I run it overnight it's not nice that it ties up the computer.

[JigPu]

Hard drives write to all the platters at the same time, so they would be missing some of the bits from each byte of the file they recovered.
Very true. Single-platter drives wouldn't be affected by this though, and depending on how HDs write to the platters it may be possible to recover chunks as large as 512 bytes. If the file is defragged you could theoretically recover up to (1/Platters*100)% of the data for a file of up to a few MB.

Still, unless you have a significant majority of the pieces, it's likely going to be darn near impossible to figure out exactly what the raw bits on the chunk you picked up mean. File recovery programs have a hard enough time recovering data from a drive which has been reformatted and reinstalled, and they have access to almost all of the original data!

But a better idea than shredding is to sandpaper the platters to remove the magnetic coating. No way that can be recoverable! No idea what the coating is made of, so as the Blend It guy says, "Don't breathe that!"
I wonder just how tough the coating is... I don't imagine its very tough at all since its likely a magnetic film which has been placed with CVD or something. The substrate is likely glass or ceramic according to Google, so probably not something you'd want to breathe in :D If only I had a dead drive lying around...

JigPu

[Luie]

Or dd it.
http://www.marksanborn.net/howto/wiping-a-hard-drive-with-dd/

[MadMan007]

Ok, I thought DBan was slow. I was wong, the Eraser program for Windows is much much slower. Just be sure to use the DBan 'beta' v2.x it has improvements for modern chipsets and CPUs.

[WiSH2oo0]

I formatted my HDD's then did 7 passes w/ that Eraser program that thegreek posted, is that good enough to sell my HDD's now?

[thideras]

I formatted my HDD's then did 7 passes w/ that Eraser program that thegreek posted, is that good enough to sell my HDD's now?Technically, if you know how the drive was erased, you can get the information from it...

Unless you had really super sensitive information (at which point the drive should be shredded, see the first post), it is fine.

[hansen]

Overwrite the entire disk with zeroes just one time, and even the recovery companies gives up.

[thegreek]

Overwrite the entire disk with zeroes just one time, and even the recovery companies gives up.

this is true for modern hard drives, not so true for older hard drives but re-write it a couple times if you're paranoid. Also, if you do a RAID0 the data is stripped between 2 drives, split these drives and overwrite them once pretty much eliminates any chance of recovery.

[madhatter256]

Recently I scrapped a about 25 pounds worth of old hard drives. Just to be on the safe side I opened them up and took a hammer to the platters (wearing goggles of course), thus eliminating any chance of data recovery.

I took the aluminum/steel cases and scrapped them for a couple of bucks. Made $15, more than I would make selling them in working condition. Next up are the crap load of copper heatsinks I have lying around....

[jason4207]

Hard drives write to all the platters at the same time, so they would be missing some of the bits from each byte of the file they recovered.

Very true. Single-platter drives wouldn't be affected by this though, and depending on how HDs write to the platters it may be possible to recover chunks as large as 512 bytes. If the file is defragged you could theoretically recover up to (1/Platters*100)% of the data for a file of up to a few MB.

Still, unless you have a significant majority of the pieces, it's likely going to be darn near impossible to figure out exactly what the raw bits on the chunk you picked up mean. File recovery programs have a hard enough time recovering data from a drive which has been reformatted and reinstalled, and they have access to almost all of the original data!



JigPu

In what fashion do they write at the same time to all platters...kind of like RAID0?

I ask b/c if that is the case then why is a single platter 250GB drive so much faster than a 2 or 3 platter 250GB drive?

I would think that writing the data to all platters at the same time would trump the speed delivered by a higher aerial density on the single platter drive, but that isn't the case.

[cozmo_d]

I rip 'em apart and make wind chimes out of the platters.

thats what I do too heh

take um apart & they make great throwing stars I even use one platter for a mirror works great in tight spots sometimes

[MadMan007]

Do the platters possibly contain any hazardous materials? I might make something out of an old 8GB HD. Dunno though, it's got sentimental value since it's from my very first self-built PC and it still works :o

[Audioaficionado]

Do the platters possibly contain any hazardous materials? I might make something out of an old 8GB HD. Dunno though, it's got sentimental value since it's from my very first self-built PC and it still works :oRust and that shouldn't be hazardous unless you grind it up and deliberately breath it in.

[MooMasster716]

http://16systems.com/zero/

I find it interesting that no one has taken on this challenge that basically involves reading the file names off a hard drive that has been overwritten with zeros once. I figured a university or professional drive recovery company would have accepted.

[Blazing fire]

I vote for sticky except that the tittle could be better. Like "how to securely erase a HDD"