Completely erase a laptop's harddrive

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DavidH
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Completely erase a laptop's harddrive

Postby DavidH » Wed Jun 01, 2011 1:44 am UTC

Hello,

I googled around abit, and was a little overwhelmed. I was wondering if anyone can recommend me a program that will completely erase my laptop's harddrive reasonably securely. I intend to sell the thing, and I have a lot of personal data I wouldn't want recovered.

The laptop is currently running windows 7, and I'm going to install a new copy of windows 7 after the harddrive is completely wiped. Apparently simply reinstalling windows 7 (which I tried) leaves a ton of files.

ajd007
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Re: Completely erase a laptop's harddrive

Postby ajd007 » Wed Jun 01, 2011 2:02 am UTC

Use something like eraser
I'm not sure what the consensus is on how many passes are necessary to ensure irrecoverability, but one or two passes should be enough for normal uses. If you're really paranoid, you can go with more.

Edit: fixed link

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hotaru
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Re: Completely erase a laptop's harddrive

Postby hotaru » Wed Jun 01, 2011 2:48 am UTC

just pull the hard drive out and put a new one in. if someone is going to try to recover your deleted files, there's really no secure way to stop them short of destroying the drive.

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EvanED
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Re: Completely erase a laptop's harddrive

Postby EvanED » Wed Jun 01, 2011 2:58 am UTC

hotaru wrote:just pull the hard drive out and put a new one in. if someone is going to try to recover your deleted files, there's really no secure way to stop them short of destroying the drive.

Uh what?

If you said that "doing more than one pass overwrite isn't really worth it", then yes, you'd be correct. But not doing that if you know better is simply stupid IMO. I bet that if you gave a drive with stuff on it to random people and told them how to put it into their computer and format it, you'd get more people at least look at what's on it than format it without looking. By contrast, after an overwrite, recovery is basically theoretical.

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Cheezwhiz Jenkins
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Re: Completely erase a laptop's harddrive

Postby Cheezwhiz Jenkins » Wed Jun 01, 2011 4:49 am UTC

Which level of "completely erased" are you going for - stand-up-to-CIA-inspection? Or just make-it-so-commercial-software-can't-find-it? The latter is achievable, the former, not so much (at least, not with any certainty).

If you just don't want your ex to be able to bust out the credit card and use some program to recover things, or similar, like adj007 said - overwrite the hdd. Do it multiple times, if you want to feel safe. (A random thought - you might afterwards encrypt the whole drive with truecrypt -use a long, random password AND a keyfile, then get rid of both. Then, I dunno, overwrite it a few more times just because. :D )

As for theoretical "I can't tell who might come looking..." organizations, thermite is great for destroying teh SEKRUTS. No way to protect against something if you don't know what it is.
That explosion was so big it blew off his mullet :-O

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hotaru
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Re: Completely erase a laptop's harddrive

Postby hotaru » Wed Jun 01, 2011 5:04 am UTC

EvanED wrote:If you said that "doing more than one pass overwrite isn't really worth it", then yes, you'd be correct. But not doing that if you know better is simply stupid IMO. I bet that if you gave a drive with stuff on it to random people and told them how to put it into their computer and format it, you'd get more people at least look at what's on it than format it without looking. By contrast, after an overwrite, recovery is basically theoretical.

it's not theoretical. with the right equipment and enough time (several years to recover a couple hundred bytes in the one case that i know of), it can be (and has been) done. one pass might be worth it if you're planning on giving the drive to someone malicious, but it'd really be better to just not give them the drive. if you're giving it to someone who doesn't hate your guts, formatting the disk is enough.

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cphite
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Re: Completely erase a laptop's harddrive

Postby cphite » Wed Jun 01, 2011 2:44 pm UTC

DavidH wrote:Hello,

I googled around abit, and was a little overwhelmed. I was wondering if anyone can recommend me a program that will completely erase my laptop's harddrive reasonably securely. I intend to sell the thing, and I have a lot of personal data I wouldn't want recovered.

The laptop is currently running windows 7, and I'm going to install a new copy of windows 7 after the harddrive is completely wiped. Apparently simply reinstalling windows 7 (which I tried) leaves a ton of files.


Go to http://www.dban.org/

Download their app, and follow the instructions to make a bootable disk. Boot to that disk and follow the instructions.

This app will completely, utterly, and permanently erase your hard drive. If you're extra-paranoid or just have lots of spare time, it'll give you the option for multiple passes - but frankly one pass is more than enough to thwart basically anyone trying to recover the data... okay, maybe the FBI or CIA have some tricks they could use, but frankly if those guys are looking at your laptop in the first place...

The bottom line is, the guy you sell your laptop to isn't going to find your pr0n collection.

yewbie
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Re: Completely erase a laptop's harddrive

Postby yewbie » Wed Jun 01, 2011 3:43 pm UTC

Just install something like http://en.wikipedia.org/wiki/BeOS BeOS then no one will want to use it.

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DavidH
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Re: Completely erase a laptop's harddrive

Postby DavidH » Wed Jun 01, 2011 10:44 pm UTC

ajd007 wrote:Use something like eraser
I'm not sure what the consensus is on how many passes are necessary to ensure irrecoverability, but one or two passes should be enough for normal uses. If you're really paranoid, you can go with more.

Edit: fixed link


I tried using this, but I'm running into the problem where I'm trying to format the drive eraser itself is on! Is there a way to make eraser boot from a USB? Or something like that? I couldn't find it on their forums.

ajd007
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Re: Completely erase a laptop's harddrive

Postby ajd007 » Thu Jun 02, 2011 12:16 am UTC

DavidH wrote:
ajd007 wrote:Use something like eraser
I'm not sure what the consensus is on how many passes are necessary to ensure irrecoverability, but one or two passes should be enough for normal uses. If you're really paranoid, you can go with more.

Edit: fixed link


I tried using this, but I'm running into the problem where I'm trying to format the drive eraser itself is on! Is there a way to make eraser boot from a USB? Or something like that? I couldn't find it on their forums.


You need to boot your computer from a different hard drive. You can't format the drive that you're running the operating system on. Ideally, you want another computer or hard drive that has windows running and install eraser there. Then connect the hard drive you want to sell and format it with eraser.

Alternatively, in eraser use the option to purge the empty space on your hard drive. This will allow you to securely remove any old data remaining on the drive without formatting the entire hard drive. This way, you don't need another hard drive or computer.
To do this right click on "my computer" go to "eraser" and then select "Erase Unused Space"
More info on this and other things you can do with eraser can be found here: http://bbs.heidi.ie/viewtopic.php?f=35&t=6354

This site has some more info if you're interested: http://cybercoyote.org/security/purge.shtml

Carnildo
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Re: Completely erase a laptop's harddrive

Postby Carnildo » Fri Jun 03, 2011 6:38 am UTC

hotaru wrote:just pull the hard drive out and put a new one in. if someone is going to try to recover your deleted files, there's really no secure way to stop them short of destroying the drive.

A single zero-fill on a modern hard drive will stop anyone short of the CIA. If you're worried about the CIA reading your drive, then yes, destroying it is your best bet.

cphite
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Re: Completely erase a laptop's harddrive

Postby cphite » Fri Jun 03, 2011 5:36 pm UTC

DavidH wrote:
ajd007 wrote:Use something like eraser
I'm not sure what the consensus is on how many passes are necessary to ensure irrecoverability, but one or two passes should be enough for normal uses. If you're really paranoid, you can go with more.

Edit: fixed link


I tried using this, but I'm running into the problem where I'm trying to format the drive eraser itself is on! Is there a way to make eraser boot from a USB? Or something like that? I couldn't find it on their forums.


Which is why I suggested DBAN, since it runs from the media you boot it from and is therefore able to erase your system drive.

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Re: Completely erase a laptop's harddrive

Postby archeleus » Sun Jun 05, 2011 7:00 am UTC

(Someone may have already suggested this)

DBAN.
I write a blog rant here.

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tendays
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Re: Completely erase a laptop's harddrive

Postby tendays » Sun Jun 05, 2011 1:24 pm UTC

I can't believe no one has suggested DBAN yet. That should solve the OP's problem...
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archeleus
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Re: Completely erase a laptop's harddrive

Postby archeleus » Mon Jun 06, 2011 7:51 am UTC

tendays wrote:I can't believe no one has suggested DBAN yet. That should solve the OP's problem...


cphite wrote:Go to http://www.dban.org/


archeleus wrote:(Someone may have already suggested this)

DBAN.
I write a blog rant here.

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DavidH
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Re: Completely erase a laptop's harddrive

Postby DavidH » Tue Jun 07, 2011 5:13 am UTC

archeleus wrote:
tendays wrote:I can't believe no one has suggested DBAN yet. That should solve the OP's problem...


cphite wrote:Go to http://www.dban.org/


archeleus wrote:(Someone may have already suggested this)

DBAN.


So yeah, I went with DBAN.

It worked very nicely! :D

Thanks for the helpful advice!


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