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A Geek Raised by Wolves - Comments on Data Recovery [entries|archive|friends|userinfo]
jessekornblum

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Comments on Data Recovery [Jun. 18th, 2006|01:48 pm]
jessekornblum
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My friend cipherpunk posted a great article about data destruction. While I think he's on the right track, I'm not sure his advice is entirely practical for the everyday users. Sure, large organizations can have a dedicated data destruction coordinator who can oversee that every drive is overwritten or melted down. But for the rest of us, the amount of effort needed to securely wipe a drive should be the minimum necessary to protect us against the reasonable threat.

The reasonable threat, and to his credit cipherpunk does encourage people not to paranoid, is that your old drive will be bought and connected to a new system in an ordinary manner.

As such, here is my opinion on what to do with your used hard drive to protect your data:
  1. Smash the drive, broadside, four times with a hammer, halfway between the center and the edge of the drive at each of the compass points.
That's it! Aside from being some great stress relief, if you're lucky enough to hit the drive head it makes a really cool PING! sound. The hammer will also break the mechanism that spins the drive making it impossible to get any data out without taking the drive into a clean room. Only specialized forensic firms have such clean rooms and access to them isn't cheap. Unless you're carrying around secrets for nuclear weapons (and I hope you know you are) there's no need to go any further.

Yes, this method means that you won't be able to sell your old drive on EBay, but it will keep your credit card numbers, diary entries, and goat pr0n out of the hands of others. In my opinion, losing ten bucks on the sale of a used hard drive is worth the peace of mind.
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Comments:
[User Picture]From: granting
2006-06-18 06:39 pm (UTC)
Eh.

To me the most important thing to keep in mind is who is your adversary. For anyone short of Osama, a one write with DBAN will do the trick easily.

Actually the most interesting work I've seen in this area lately has been by Dr. Gordon Hughes out at UCSD. Here's his erasure stuff: http://cmrr.ucsd.edu/Hughes/subpgset.htm
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From: (Anonymous)
2006-06-18 06:50 pm (UTC)

NIST guidelines

J--,

NIST has guidlines for media sanitization that we follow at my client site. Publication 800-88 covers the three methods for drives: Clear, Purge and Destroy. Interestingly, they approve of the S-ATA "Secure Erase" command as an acceptable method for purging the drives if followed by a degaussing with NSA/CSS approved wand.

But the Destroy option is the most fun. "Disintegration, Pulverization, Melting and Incineration" are approved techniques, but we usually sand the platters and then put them into a classified shred bag to be shredded, before they are incinerated and sent to a classified land fill.

Just like "Compress before encrypting", you should also shred before incinerating. It just doesn't work as well in the other order.

-- T.
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From: (Anonymous)
2006-06-18 10:06 pm (UTC)

Re: NIST guidelines

I forgot to mention that NIST requires the drives be incinerated in an EPA-approved incinerator. You don't want to create polution while you prevent access to the drives!

-- T.
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[User Picture]From: cipherpunk
2006-06-19 03:37 am (UTC)

Re: NIST guidelines

So what are the EPA guidelines for environmentally responsible aluminothermic reactions? :)
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[User Picture]From: capnbuckle
2006-06-21 03:38 am (UTC)

Re: NIST guidelines

Hmmm. I happen to own an oxy-acetylene cutting torch. I just might be able to reach the Curie point... ;)
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From: (Anonymous)
2006-06-19 07:35 am (UTC)
While not too field expedient, an afternoon with a friend's Barrett .50 will do wonders on insuring none of your data can be peeled off in the clean room...

http://www.23.org/~chs/gallery/defconx/shoot/pict2205f.jpeg :)
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From: (Anonymous)
2006-07-25 08:46 pm (UTC)

Recovering files on OS X

J--,

For some reason this posting came up again on Bloglines today, over a month after you posted it.

Over the weekend we had a chance to test data recovery against rm on Mac OS X. H-- accidentally deleted a LaTeX file and called me in a panic. Luckilly the file was over a few days old and had certainly been flushed out of cache as well as had a few swap files around, so we did the old fashioned way to recover it:

sudo cat /dev/rdisk0s3 | strings | less

She searched for a few keywords from the document and was able to recover the entirety of it, minus any formatting. Let's hear it for plain text documents!

T--
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