question How to effectively delete data from magnetic media? I mean professional way.

[Kombi]

Hi everyone,

I have many disks and storage media, some of them are physically damaged.

I need to find professional way of deletion data from those disks and tapes. I would like to do it in my office. I don't want to pass them to utilization companies, unless I am sure they are erased.

Any experiences ???

 

[Chewy509]

Depends on how paranoid you are...

If the disks are still serviceable and in working order, using a tool like DBAN is good enough. http://www.dban.org/

If the disks can't be read by a PC/server, then you need to physically destroy the platters. The most common method is to remove the platters from the HDD casing, then apply some form of abrasive to the platters surface. (Some use a grinder, some use sandpaper, and some use a plasma torch, and I've heard rumors of thermite as well :rambo: ). Another option is to shred the platter, but this needs industrial equipment.

For tapes, the easiest method is to open the casing, and physically destroy the media. There are a couple of methods, but a popular one is just to use a shredder. (Place the end of the tape in the shredder, and let the shredder pull the tape of the reel). But best to use a high quality cross shredder with a 1mm x 2mm cut (or there about).

For government standards, NIST has the following available: http://www.nist.gov/manuscript-publication-search.cfm?pub_id=50819

PS. Welcome to SF

 

[Mercutio]

My normal method of data destruction involves a high place and some concrete, or a hammer. Throw the actual tape in a paper shredder if you're worried about that.

 

[time]

You can get bulk erasers for tapes, but hard drives need a professional degausser. Note that modern media will be unusable after magnetic erasure because of the loss of servo tracks. So you might as well physically destroy the media, which is considerably cheaper.

I disagree slightly with Chewy509 - any shredder at all would be enough to stop data recovery from tape. In fact, a pair of scissors and some patience would probably be enough! Or you could burn it, drop it in paint, etc.

Ddrueding favors drilling a couple of holes through a hard disk drive as the easiest way to guarantee full loss of data.

 

[Bozo]

There are companies that will come to your office and shred a hard drive while you watch.

 

[ddrueding]

Ddrueding favors drilling a couple of holes through a hard disk drive as the easiest way to guarantee full loss of data.

Indeed. This is the quickest way I've found. Keep in mind that, in theory, the platters could be removed, scanned while laying flat on a table, and some of the data might be recovered. At a cost of at least $10k per disk. But if you need more of a "sure thing", nothing short of shredding or thermite should be acceptable.

 

[time]

A drill would probably distort the platters as well as contaminating the interior with magnetic debris. I very much doubt that anyone has equipment that can scan a platter lying still on a table - the tracks are only 75 nanometers wide (including any guard space) and I'd guess there are between 10 and 20 million bits encoded in each track.

Remember that for these things to work at all, the heads are flying only about 30 molecules of air above the platters. They're already state of the art; I don't believe there's alien technology somewhere that can do what you suggest.

 

[Mercutio]

I don't believe there's alien technology somewhere that can do what you suggest.

A scanning electron microscope can resolve images down to .2nm. I suspect that pissing off the wrong first world power could lead to a demonstration of just what the state of the art in data recovery really is.

I pretty much figure that at the point that the drive has been purposefully head-crashed, it's probably dead enough from a practical standpoint.

 

[Newtun]

If the disks are still serviceable and in working order, using a tool like DBAN is good enough. http://www.dban.org/

. . .
​

For government standards, NIST has the following available: http://www.nist.gov/manuscript-publication-search.cfm?pub_id=50819

That publication, page 8, under "Purging", mentions Secure Erase, a built-in ATA feature.

The free Ultimate Boot CD contains HDDErase, a Secure Erase program from The Center for Magnetic Recording Research at UC San Diego. (The Ultimate Boot CD also has DBAN.) HDDErase erases "bad sectors" that have had their data relocated and are marked as unusable by the disk drive; I don't know if DBAN does that. The documentation for HDDErase also claims that there is little added benefit to overwriting a disk more than once, and I believe Secure Erase, as a native ATA command, would be faster than an "external" block-overwrite program.

 

[Chewy509]

The documentation for HDDErase also claims that there is little added benefit to overwriting a disk more than once, and I believe Secure Erase, as a native ATA command, would be faster than an "external" block-overwrite program.

From my understanding on modern HDDs, that's quite correct. ( http://www.anti-forensics.com/disk-wiping-one-pass-is-enough ) A single pass is all that is needed to stop most people out there. Multi-pass erase is only needed if you need to satisfy some government regulation or contract or you work for the DoD (or similar) and have rules/procedures to follow.

My only concern on Secure Erase, is that some vendors have been found to not implement the function correctly... or at all... Again, depends on how paranoid you are, and who your enemies are, and how much resources and time they are willing to recover anything off the drive.

For most people on the street, a single pass with DBAN on a working drive, a drill into the platter (as some have mentioned) on a non-working drive, and a tape removed from the reel and cut a few times or coarsely shredded is enough.

PS. For those interested: http://static.usenix.org/events/fast11/tech/full_papers/Wei.pdf

 

[Bozo]

Partition Wizard will wipe a hard drive with zeros or 'ones' up to 7 times for DoD cleaning.

 

[Newtun]

My only concern on Secure Erase, is that some vendors have been found to not implement the function correctly... or at all...

I would be interested if you have some references for those assertions.

 

[Chewy509]

The paper I linked to, section 3.2.

Support and implementation of the built in commands varied across vendors and firmware revisions (Table 1). Of the 12 drives we tested, none supported the ACS-2 “SANITIZE BLOCK ERASE” command. This is not
surprising, since the standard is not yet final. Eight of the drives reported that they supported the ATA SECURITY feature set. One of these encrypts data, so we could not verify if the sanitization was successful. Of the remaining seven, only four executed the “ERASE UNIT” command reliably.

Drive B’s behavior is the most disturbing: it reported that sanitization was successful, but all the data remained intact. In fact, the filesystem was still mountable. Two more drives suffered a bug that prevented the ERASE
UNIT command from working unless the drive firmware was recently reset, otherwise the command would only erase the first LBA. However, they accurately reported that the command failed.

As for who they are, no idea, you would have to contact the authors of the paper to find out.

 

[time]

AFAIK, SSDs are not magnetic media. If Secure Erase is good enough for NIST, it's good enough for me.

 

[Newtun]

The paper I linked to, section 3.2. ... As for who they are, no idea, you would have to contact the authors of the paper to find out.

That is unfortunate - only 4 of the 12 drives successfully Secure Erased. But that was for "Flash-Based Solid State Drives". (Surely OCZ is not among the bad ⅔. ;-))

I hope the Secure Erase BA for "rotating-platter" drives is better than 333.

 

[LunarMist]

AFAIK, SSDs are not magnetic media. If Secure Erase is good enough for NIST, it's good enough for me.

Have you spent any time at NIST or hired firmer employees?

 

[Chewy509]

I hope the Secure Erase BA for "rotating-platter" drives is better than 333.

I would certainly hope so. However how much do you trust vendors to own up to the fact that their implementations are broken, or even to provide firmware updates in cases when it wasn't operable, or even missing. The way most vendors treat firmware these days (from everything from smart tvs, bios's/EFI, mobile phones), I would certainly expect to see some broken implementations out there.

However, if the use of secure erase is needed for your infrastructure, then make sure that any samples you are given to test with actually have the feature and work as advertised, (and can be independantly verified). Otherwise need to fallback to with the FORMAT UNIT command (writes 0's to all sectors), use a tool like DBAN, or go with physical destruction.

PS. Secure erase was added in the ATA-7 spec, but is only optional as part of the spec.

 

[CougTek]

Damn! 16 answers and no one got it right. The safest way to delete data from a magnetic drive, or to destroy about anything smaller than a building for that matter, is to give it to me and let me take care of it. You guys sure don't learn fast.

 

[LunarMist]

Yes, that was my first thought.

 

[Kombi]

Thanks for replies!!

I need something more professional than scissors and hammer ;-)
You mentioned about Garner professional degausser, but I need something in a better price...
Maybe some of you know others, cheaper models???

 

[Chewy509]

There are heaps out there, most starting at US$2000, and climbing rapidly upwards. Use Google to find somewhere close to where you are, so you can see it in action...

Just depends what certifications/standards you need to comply with, and if you want DoD/NSA/Government approved equipment or not...

FYI, For modern HDDs, you need something that can do 5000 Oersteds, due to the new perpendicular storage technology...

PS. Thought this one was cool, perfect for Coug and DD... http://www.periphman.com/degaussing/degaussers/mhdd.shtml

 

[blakerwry]

Indeed. This is the quickest way I've found. Keep in mind that, in theory, the platters could be removed, scanned while laying flat on a table, and some of the data might be recovered. At a cost of at least $10k per disk. But if you need more of a "sure thing", nothing short of shredding or thermite should be acceptable.

I agree that the drill is fast, but I keep breaking bits. I've used hitachi (cheap) and dewalt (decent) bits. Do you experience the same problem? recommendations?

 

[blakerwry]

+1 for dban as well.

 

[ddrueding]

I use Dewalt, preferring their titanium bits. The smaller bits do the job faster, but break more easily. I use the 1/4" most of the time. Good compromise between strength and speed.

 

[merrick]

I found something:

http://prodevice.pl/products/1-0-deagusser-prodevice-asm120.html

This degausser ProDevice ASM120 generates magnetic field of 11 000 Gauss, so it's pretty good for your media storage!

But I don't know what is the price.

 

[prsh]

I found something:

http://prodevice.pl/products/1-0-deagusser-prodevice-asm120.html

This degausser ProDevice ASM120 generates magnetic field of 11 000 Gauss, so it's pretty good for your media storage!

But I don't know what is the price.

I've already tried this one and I must say it has awesome price / quality ratio. Maybe it's not piece of art but ethernet and software to manage and report is a great advantage - especially when you have services on site or have to rent it to customer.

 

[DavidDen]

Shredding methods for you

Hi everyone,

I have many disks and storage media, some of them are physically damaged.

I need to find professional way of deletion data from those disks and tapes. I would like to do it in my office. I don't want to pass them to utilization companies, unless I am sure they are erased.

Any experiences ???

For traditional storages which are not physically damaged, you can use software-based shredding method; I recommend Farstone Shredding software(http://www.farstone.us/download/TotalRecovery/TotalShredder_7.04.1.exe). For current hard drives, some experts say that only two rounds overwriting are enough. Please refer to http://en.wikipedia.org/wiki/Data_erasure for details.
For traditional Storages physically damaged, you should use degauss or othe physical destruction. You can download "Unclassified Computer Hard Drive Disposition" (PDF). U.S. DoD. 2001. Retrieved 2010-07-20. http://iase.disa.mil/policy-guidance/asd_hd_disposition_memo060401.pdf.
But for SSD hard drives, above software-based method doesn't work; You need send special ATA command to do this("For sanitizing entire disks, built-in sanitize commands are effective when implemented correctly, and software techniques work most, but not all, of the time."). Please refer to "Reliably Erasing Data From Flash-Based Solid State Drives" for details. As I know, Farstone is developing some shredding tool to send special built-in sanitize commands, which can even shred over-provision space of SSD. If you need that, I'll update related information for you.