Storage

Five ways to intentionally destroy your data

Scott Lowe presents five ways to accomplish your data destruction goals when destroying magnetic media.

A critically important part of data lifecycle management is destroying data at the end of a medium's useful life. If this step is overlooked, it can lead to disastrous results.

The method by which data on a particular medium is destroyed is dependent on that medium type. Data destruction mechanisms must be employed for paper records, magnetic media including tapes and hard drives, and storage mediums such as flash drives or CDs/DVDs that might have sensitive information.

There are multitudes of ways you can make sure that the chances of anyone ever recovering your data are slim to none. Here are five recommended methods for destroying data on magnetic media.

1: Shredding

There are services that will literally shred a hard drive. Take a look at this impressive video, which shows a drive being completely destroyed. For someone to come back after the fact and attempt to reconstruct it -- particularly when a single drive's debris is mixed with other debris -- would be almost impossible.

In many cases, you can ship the drives to the destruction company but, in order to maintain a clear and responsible chain of custody, many services will come to you so that you don't have to worry about what happens during transit. Or, you can buy your own mega-shredder, but those can be pretty expensive.

From a "fun to watch" factor, this method can't be beat!

2: Degaussing

Hard drives are nothing more than bottles of data held in place by magnetic glue. By removing the magnetic glue, you can create a breakdown of the underlying bits and bytes and scramble them in a way that's pretty tough to recover from. If the degaussing device used is good enough, you'll destroy all of the bits and bytes at the user level as well as the low-level formatting that makes it function as a drive. (If you're serious about data security, you'll use a powerful degausser.)

Although degaussing might be looked at as a way of simply erasing a drive, it's actually a destructive mechanism, though it's not nearly as fun to watch as a shredder.

Powerful degaussers will also render inoperable a drives servo motors and will damage the spindle motor of the drive. It truly is a paperweight when you're done.

A really good degausser is expensive, but it doesn't cost as much as a really good shredder, and it might be enough for your needs. Also, it's a fast process. Take a look at this YouTube video of a hard drive degausser in action.

3: Department of Defense level data overwrite

If you've been in IT for any period of time, you probably know that deleting a file really doesn't mean that the file is no longer retrievable -- it simply means that the operating system has removed it from your view. Retrieving files deleted by the operating system is a pretty trivial task.

So, how do you make sure that your deletion process really achieves your data protection goals? Use a process that meets Department of Defense guidelines for data overwrite. From a simplistic view, this process involves overwriting each area of the disk multiple times with different kinds of data (patterns).

There are all kinds of programs intended to securely delete files and even entire hard drives. For example, the SDelete program from Sysinternals allows you to securely delete a single file, while programs such as East-Tec DisposeSecure extend the protection to full hard drives and include critical validation reports showing the success of the process. Take a look at Active@ KillDisk and Darik's Boot And Nuke (DBAN), which were recently profiled by my fellow TechRepublic blogger Rick Vanover.

4: Smelt it

The most committed people may try to find a way to thwart your data destruction efforts, even if you physically destroy the hard drive or wipe its magnetic field.

The problem: Even after destruction, the hard drive is still in the same physical state, even if it no longer has a magnetic field or is in thousands of pieces.

The solution: Perform a process that changes the hard drive from a solid into a liquid. This is an extreme, but it may be necessary for some kinds of data.

These guys provided a nice overview of the backyard process they went through that guarantees (even more than the methods described above) no one will be reading data from this physical medium every again.

On a serious note, there is a temperature at which magnetic media loses its magnetism and is no longer able to hold data together. Called the Curie point, after this temperature, the bits and bytes are no longer neatly ordered. Since different kinds of metals are used in varying kinds of magnetic media, I've used the definitive resource -- Wikipedia -- to show you what kinds of temperatures are the Curie points for each metal.

Substance Curie temp °C
Iron (Fe) 770
Cobalt (Co) 1130
Nickel (Ni) 358
Iron Oxide (Fe2O3) 622

So, whether you smelt it or incinerate it in some way, get your media above these temperatures or change its state to liquid, and your data is much likelier to be safe.

5: Encrypt from the beginning

While this method isn't purely destructive in nature, encrypting the contents of your storage as a routine practice can help you protect against prying eyes when it comes time to dispose of the media, particularly if you store the decryption key away from the media. The downside to this method is that it's not 100% foolproof and can be subverted by someone who really wants the data. The upside is that the attacker needs physical access to the computer's operating system.

What works for you?

How do you accomplish the goal of ensuring that your data remains your data as part of your organization's information security plan? Share your data destruction methods in the discussion.

About

Since 1994, Scott Lowe has been providing technology solutions to a variety of organizations. After spending 10 years in multiple CIO roles, Scott is now an independent consultant, blogger, author, owner of The 1610 Group, and a Senior IT Executive w...

51 comments
TonyBaldi
TonyBaldi

and not as effective, but the old hammer trick, if done properly,will make the data inaccesible to 99% of people. Nobody would try to recover the data if they see that the hard drive has been destroyed.

martin.reading
martin.reading

Take your drive and hold an old drill bit to it - position drive vertically in a vice and tighten wedging the drill bit in place. As you do it goes into the platten and shatters. Remove, shake and job done

Con_123456
Con_123456

unless you have power to destroy that server and all its backed-up data.

dcolbert
dcolbert

The problem with most of these methods is how *practical* they are for a given operation. Overwriting is going to be the most common method employed. Degaussers are expensive, hard to find, and can be dangerous. Additionally, they render the drive inoperable after use. They destroy it. Software erasers are slow and prone to issues. You'll probably have more drive space than you can wipe in a timely manner and will need to let drives run erasing, unattended. Check out the WeibeTech Drive Erazer for a hardware based, dedicated secure-overwrite solution that is relatively fast, compact and in my opinion, the way to go if you can't afford the much more elaborate or dangerous methods described here. They're the only ones I am aware of offering a solution like this. It is relatively expensive, but also relatively cheap, depending on how you look at the problem and the solution.

Old Timer 8080
Old Timer 8080

The best way the DoD had to secure data on the DD-29s we sent with every Cray... The top cover was modified to have a 45 caliber pistol mount that would point through the platters. In the case of a security breach, the duty officer was responsible to pull the trigger on about 20 DD-29s....While they were operating.....

oldbaritone
oldbaritone

was fun when I was in the USMC and we needed to destroy secure equipment. It's really spectacular, and all that's left is slag.

jc
jc

I see quite a few posts (some that actually sound like a lot of fun) that just make the drive mechanism stop functioning, or cause partial damage to the platters. Don't assume that these methods are adequate if you are handling sensitive data. This goes double if you are being paid to destroy drives/data by your customers. Some may think the cost is prohibitive to later pull the platters and use extensive recovery procedures, but it is all relative. Corporate espionage, cyber crime, and even celebrity news have huge payoffs. I'm sure a tabloid that would pay $1M for the first pic of someone's new kid, wouldn't bat an eye at dropping a few grand to get what they want off of discarded drive platters. Bad publicity costs $$ too. Your methods should be adequate to the level of sensitivity of the data on the media. Additionally, you don't want to be the fall guy when a company is faced with defending themselves against a major compliance violation. :)

lshanahan
lshanahan

Seriously. A guy I work with has a friend who is a forensic specialist in data recovery. They ROUTINELY recover data from smashed drives. They pound them with hammers, throw them off the tops of buildings and many more severe forms of destruction. So just hitting it with a hammer may stop your average hacker, but it isn't totally foolproof.

ilovesards
ilovesards

i think the cheapest and easiest is put it on hydrochloric acid for one night. then thow it to the sea where there=it will biodegrade by sea salt.

realvarezm
realvarezm

u can use your microwave oven to destroy any kind of storage media, although probably will fry tour oven too :)

learon
learon

dd if=/dev/zero of=/dev/sda This will write all zeroes to the HDD. Repeating this two or three times will exculde any possibility of re-reading data.

rockne1865
rockne1865

Burning barrel I live in the mountains a nice Bonfire I use old pallets stack them & a little diesel with the drives on top!

Who Am I Really
Who Am I Really

if a disk is still functional, I do a four step process and then recommission it a> HDDErase and / or DBAN b> SpinRite to check SMART data for any sector re-allocations c> re-partition and format to FAT32 d> fill the disk to 100% capacity with cluster length files (32,768) install the disk into an external enclosure or into a system as a data disk

stonyb31
stonyb31

I take-em apart spin them up, and drag a screwdriver across the disk, scoreing physically back and forth. Cheap, and effective. I also hold them against a running car alternator after this. I believe this does the trick. Anyone disagree?

Jaqui
Jaqui

actually, 2 things are missing. dban needs to be reconfigured for it to meet the DoD requirements. The defaults are not strong enough in the data destruction to do so. There is an option though, Eban. [ dban with DoD level defaults. ] and it's actually been approved by the R.C.M.P. for data destruction purposes. Freegeek Vancouver uses Eban on ALL hard drives that are functional. They have a crusher for non functional drives as well. Not only is a crusher fun to watch, but it's fun to use.. :D [ they crush any hard drive smaller than 50 gigs even if it is functional ]

paradoxstorm
paradoxstorm

We are a NAID AAA-certfied facility providing mobile document shredding and hard drive destruction services. We use a Hard Drive Crusher from EDR Solutions. It does a fantastic job of destroying a drive in about 15 seconds. It rams a 3" diameter piston through the platters using about 12,000 pounds of force. It's a lot of fun. Here's a link to a demo video. http://www.edrsolutions.com/europe/

bensykes
bensykes

Use an SSD instead, forget that magnetic stuff

fvazquez
fvazquez

I normally open the used hard drive in order to get the neodymium magnets. I use them in several ways: you may glue'em on a board and use'em as a tool hanger in the workshop, a small magnet resists up to 20 pounds... so I take the disc out at the same time; bye bye data... :)

Realvdude
Realvdude

I use a program called Eraser for Windows, free from http://heidi.ie, which has options from a single pass to a 35 pass. It will do individual files and also free space. It also will do a secure move for files. It provides options in the context menu, so it is easy to use.

douglas.gernat
douglas.gernat

Keep the hard drives for a month or two, then take them to the target range. A 12guage ensures a good splatter, and seperation of parts...

Spitfire_Sysop
Spitfire_Sysop

If you want a nice surefire method that is pleasantly low tech a simple press can be made. This is the method used at the local technology recycling center. They have a screw mechanism from a big bench vise and instead of two flat clamping surfaces one of the sides just has a pointed cone. You place your drive in the vice and screw the cone straight through the housing and all the platters. This physically destroys the mechanical motion and the platters holding the data. I'm sure that you could argue that bits still exist but I'm confident you would not be able to get anything useful after the unreasonable ammount of time required to find the data tracks and recover parts of them. The end result looks similar to a drive that was shot with a bullet.

Scott.Geiger
Scott.Geiger

If you really need to smelt a drive to keep the data safe I hope you are paying the 20 armed guards around you *very* well. LOL. But it is effective. The shredder also looks to be quite satisfying.

Dr_Zinj
Dr_Zinj

U.S intelligence agencies do have the ability to reconstruct multiple overwrites, degaussed, and macro-shredded drives (the kind shown in the video). All reconstruction of destroyed data involves a percentage of error in reconstruction. Obviously the smaller the pieces are shredded into, the more overwritten the drive, and the stronger and more varying the magnetic field, the harder it is to reconstruct; and the higher the reconstruction error rate. You're looking at three curves: the value of the target data, the cost of time and resources to reconstruct, and the reconstruction error rate.

brianh
brianh

I use a large set of bolt cutters to put 2 or 3 full cuts through the body of the drive and platters. Like cutting a pie.

Peter9009
Peter9009

If you have access to a vibrating compactor (steamroller), that could be a fun way to destroy your drives.

dave the IT guy
dave the IT guy

I usually just drill holes in my dead drives, but I have a friend who takes disks out to his father-in-law's farm, sets them up on a fence rail, and uses them for target practice with his Glock 9mm.

bimjimmy
bimjimmy

There's an old DOS command DEBUG which writes zeroes to every sector on the drive, and is mainly a utility for formatting new drives. But that takes too long (hours) for today's ADD users and terabyte drives, so manufacturers sell drives already low-level formatted. Users buying new drives use FORMAT, which is a high-level format and basically just clears out and sets up only the directory structure. FDISK, by changing partitions, also screws up the directory , but as with a high-level format all the original data is still there, it just has no directory to organise it.. If you have the time and inclination you could also do a FORMAT of the drive, and then one after the other save humongously large files (like huge blank images, they can easily get up to 300 Megs or more) and by so doing rewrite most, if not all, of the sectors. But you would need to do an initial calculation as to size of the disk, size of the file, and how many times you need to save the file to disk to fill it up with irrelevant stuff. Then you would save, change the name of the file by one character, save again, and so on. If the drive is broken and you can't access it, unscrew (or break) the cover, pour in lots of salt, top up with water, and leave to sit for a few weeks. Nature's brine does wonders to destroy metal parts by etching and corrosion. If you can get the drive open, deeply scratching all the disk surfaces with a screwdriver before soaking will help tremendously.

dominic.blomfield
dominic.blomfield

look at top of the drive, unscrew 1 corner away from the armature, slide in screwdriver into gap between base and cover, push screwdriver in and down through the platters till you hit the bottom (lovely cruching sound!!) and do screw back up. Quick, tidy, perminent. Data state to paperweight in 60 seconds.

#1bobcat
#1bobcat

If your drive is none functional, it still has data. To kill ours, we use bullets. Several of us take a box of non-functioning hard drives to the range and take out our frustrations. Much cheaper than a shredding service, just as visual, just as much fun, and nearly as effective.

dhays
dhays

There is always the drill holes in the drive method, that should slow anyone down. One could also just remove the parts and destroy them individually. That is what I have done with 3.5 in floppies. After shredding a drive, take the pieces and distribute them all over the town or state, then no one would know which pieces to put together. I like the melting method, but raising the temperature to > 1130 Deg C would not be easy, especially for an end user.

pshore73
pshore73

I have been known to pull the drive from a machine then beat it with a hammer until it shaking resembles a maraca.

2rs
2rs

not really my topic - RE: your Avatar - just watched Monsters, Inc. the other night, still a great flick. I've had fun just reading the responses..Thanks!

Brian Grimm
Brian Grimm

I got to see an engine block melted with thermite once. Pretty cool. On a practical side, I wonder if a CadWeld (exothermic ground welding) shot would do anything. Might have to order one to find out...

Dr. Tarr
Dr. Tarr

Still a bit expensive, but I use a plasma cutter to chop the drives into ~ 1 inch strips, or if I'm feeling artistic I cut a spiral. what isn't vaporized is roasted, inspection of the remains reveals that the magnetic media is physically destroyed. One of the local computer forensics chaps said that with basically unlimited time and resources some information could be retrieved from the slaved disks, but what little bits that remain could be elimated by making a few more passes and reducing the slice size to 1/2 inch, and the spiraled disks were hopeless.

dcwhitworth
dcwhitworth

That may well protect your data but is probably illegal.

SmartAceW0LF
SmartAceW0LF

Let your fingers get in the way just once when a couple of them snap together! Might take some of the knuckleheads on this forum more than one blood blister to learn this lesson.

osvath
osvath

Would my Glock 45 cal work, or does it have to be a 9mm. :)

furicle
furicle

Since there's one here anyway, I can put two 1" holes thru the drive in about 30 sec - and the platters either shatter or bend and twist so bad they're toast anyway.

DimBulb
DimBulb

also works on users.

Den Palmer
Den Palmer

I have a 5 lb sledge dedicated for the purpose. If someone can straighten and realign platters and recover the data, then I suppose I am on the hook for that. Can't say he didn't work for it!

Who Am I Really
Who Am I Really

less expensive and the resultant product is blobs of HDD lava on the shop floor

ted.watkns
ted.watkns

Now I have a target for my new 357!

dave the IT guy
dave the IT guy

dunno - you'd have to try it out. Just make sure to keep a safe distance.

scairns
scairns

Shredding, and degaussing cost ridiculous amounts of money and hardly anyone has access to these services. Pulling a drive apart takes a lot of time (comparatively speaking) and then you have to damage / destroy the platters anyway. From experience, just about everyone has access to a drill, and "metal" drill bits are cheap. If you have access to a drill press, well and good. Otherwise put the drive on a thick piece of timber (so you don't drill damage the surface under the drive) and drill away. Three or four holes later with a 10mm drill bit and you have one unrecoverable HDD. Guaranteed.

LocoLobo
LocoLobo

the hammer is cheaper than the shredder. Until you factor in the time costs. :)

dave the IT guy
dave the IT guy

yeah - at a cost of a few thousand dollars, to get bits and fragments and portions of files. Someone that wants your data that badly will find other ways to get it - all of it. They won't waste their time and money on trying to pull data from a badly damaged drive.

Who Am I Really
Who Am I Really

especially those that specialize in law enforcement forensic analysis of disks and they will recover every bit and byte from every part of the platters that doesn't have a hole through it