Eraser good enough to wipe drive before selling?

Discussion in 'privacy technology' started by Fontaine, Aug 29, 2010.

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  1. Fontaine

    Fontaine Registered Member

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    I'm selling an external drive. I want to wipe is clean. I started to use DBAN but it is estimated at 20 hours. I have three drives to do and unfortunately not that much time.
    Can i use Eraser to wipe the free space (i.e. the whole thing)?
     
  2. LockBox

    LockBox Registered Member

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    Absolutely. Since these are external drives, I would simply format the drive and then do a free-space wipe with Eraser and then delete the partition completely. DBAN would be way too slow on a USB external drive.
     
  3. Fontaine

    Fontaine Registered Member

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    Thx for the reply.
    I formatted, now i am wiping the free space. How do I delete the partition? suppose I could use google. :)
    Is it necessary to delete the partition on the drive?
     
  4. LockBox

    LockBox Registered Member

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    No, it's not necessary. In fact, if you are reselling the drives (I just noticed that), you would be better off just doing another format after the free space wipe and it would be ready to sell and ready to use by the buyer.
     
  5. chronomatic

    chronomatic Registered Member

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    Just use a Linux LiveCD and run the following command from the terminal:

    Code:
    sudo shred -fvz /dev/sdx
    where "sdx" is the name of the drive (it will probably be sda). This will wipe the whole drive with zeros which will render any data unrecoverable.
     
  6. LockBox

    LockBox Registered Member

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    Or you could........

    There are a lot of ways to do what you want to do. Any of these will work for your purposes.
     
  7. PJC

    PJC Very Frequent Poster

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    I second that. Eraser can do what you need.
    A paid solution is East-Tec DisposeSecure.
     
  8. Fontaine

    Fontaine Registered Member

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    This is weird!
    I formatted all the external drives and used eraser to wipe them. Each drive had these weird leftover files that were created from the process. They look like windows system files. Example of a few of the files from one of the drives:
    TapiUnattend.exe
    recover.exe
    javaw.exe
    KBDA3.dll

    There are a bunch more. When I noticed it, I formatted one of the drives again and wiped it again to test it out and sure enough, weird system-like files reappeared when eraser was done wiping it.

    Any ideas what the heck this is??
     
  9. dantz

    dantz Registered Member

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    I don't know why you're bothering with a file eraser on an external drive. There's no need to preserve the filesystem, as it can be easily be recreated after the wipe. A single-pass zero wipe is all you need. It would be easier and more complete to use the manufacturer's diagnostic tools to write zeros to the drives, and while you're at it you can test their health.
     
  10. TheMozart

    TheMozart Former Poster

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    Let me explain something to you.... a hard drive only has ONE LAYER able to store data. Hard drives are NOT multiple layers able to store different data over itself.

    So.... just overwrite the hard drive once with different data and voila, it's done!

    Once your data has been overwritten it's impossible for anyone to get the older data because older data was overwritten.

    If someone could get older data UNDERNEATH new data, then they would become famous overnight and all hard drives around the world would magically double in size because that would mean a 320GB hard drive could magically store 640GB data because you could store 2 different pieces of data OVER EACH OTHER lol:D
     
  11. chronomatic

    chronomatic Registered Member

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    The NIST (part of US government) says that one overwrite is all that is needed. The DoD standards you refer to were made many years (decades) ago when drive technology was different. From NIST:

    Other research has also come to the same conclusion -- data overwritten once on modern hard drives cannot be recovered.
     
    Last edited by a moderator: Sep 4, 2010
  12. TheMozart

    TheMozart Former Poster

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    HANG ON A MINUTE! Are you suggesting that if I have a 5GB HDD and I overwrite the whole 5GB with a 5GB video file, that you or someone else is able to retrieve the 5GB data that was there BEFORE I overwrote it with the 5GB video file?:blink:

    So a HDD can have 2 layers of DIFFERENT DATA exist in the ONE PLACE?
     
    Last edited by a moderator: Sep 4, 2010
  13. Klawdek

    Klawdek Registered Member

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    The way it works is this. The heads on older hard drives do not always write data in the same exact spot. It might be off a little to one side or the other. So when one thing is written it could be off a little to the left. When you overwrite that data it might write a little to the right. This leave a little bit of magnetism from the first write.

    For many years I was under the impression that to get to the overwritten file required removing the platters which requires a clean room and putting the platters in a special device. Minimum cost about 250 Million USD.

    Recently I have read a few things that implied it could be done by some kind of low level drive access.

    A man named Gutmann came up with what is known as the Gutmann 35 pass method that involved 35 overwrites to insure that the overwritten file could not be recovered.

    Recent hard drives do not have this problem so only one overwrite is necessary. Gutmann has since stated that his method is not needed with modern hard drives.
     
  14. LockBox

    LockBox Registered Member

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    You are correct. However, this is where remnants come into play. A single-pass may indeed leave the file irretrievable, but may leave file names somewhat readable enough that one could make judgments as to their contents.
     
  15. tobacco

    tobacco Frequent Poster

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    I wouldn't - it's buggy on my system (vista32). I've installed and removed it within a few days 3 times now and always go back to File Shredder - http://www.fileshredder.org/

    Set on DOD 3pass, it also changes file names to numbers & letters before wiping is complete.
     
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