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Millions of usable hard drives are being destroyed

bbc.com

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Re: Millions of usable hard drives are being destroyed

#11

Post by d33 »

Gordonjcp wrote: post #5
ReactiveJelly wrote: post #4

Defense in depth is the reason.

Okay, but a single pass of /dev/zero will destroy all the data beyond hope of recovery.

For that to work you have to trust the firmware. Overwriting with something random, saving what was fed and then cross-referencing that against the storage could work better, but there's still some non-zero chance that something you're looking for is in a buffer, unreachable part of the disk or the like.

Encrypting the hard drive and then removing the key has a better chance of rendering the data unusable.

Re: Millions of usable hard drives are being destroyed

#13

Post by treis »

Gordonjcp wrote: post #5
ReactiveJelly wrote: post #4

Defense in depth is the reason.

Okay, but a single pass of /dev/zero will destroy all the data beyond hope of recovery.

Only if you're sure 1 -> 0 is not detectably different from 0 -> 0.

There's almost certainly secure ways to delete. But not worth it for a five year old drive that may have had sensitive information on it.

Re: Millions of usable hard drives are being destroyed

#14

Post by linuxftw »

Gordonjcp wrote: post #5
ReactiveJelly wrote: post #4

Defense in depth is the reason.

Okay, but a single pass of /dev/zero will destroy all the data beyond hope of recovery.

For an actual HDD, maybe that would work. For any solid state drive, it would definitely not work. SSDs and similar spread writes across pools of blocks for 'endurance', so a 1TB drive might actually have 2TB worth of flash on it.

Re: Millions of usable hard drives are being destroyed

#15

Post by zokier »

Gordonjcp wrote: post #5
ReactiveJelly wrote: post #4

Defense in depth is the reason.

Okay, but a single pass of /dev/zero will destroy all the data beyond hope of recovery.

/dev/urandom is far better option. One problem is that writing a full drive of data can take long time vs chucking it into shredder. For example this[1] 22TB drive can do 260MB/s, meaning that doing one full disk write pass would take almost 24h.

[1] https://nascompares.com/2022/09/12/wd-red-pro-22tb-hard-driv...

Re: Millions of usable hard drives are being destroyed

#17

Post by manicdee »

Gordonjcp wrote: post #5
ReactiveJelly wrote: post #4

Defense in depth is the reason.

Okay, but a single pass of /dev/zero will destroy all the data beyond hope of recovery.

Falsehoods like this spreading through populations that consider themselves technically literate is one reason the NIST standard requires absolute destruction.

There are methods available that will allow recovery of second, third or even fourth generation data to be recovered from magnetic disks. Writing /dev/zero "over" an SSD won't necessarily accomplish what you expect either.

Re: Millions of usable hard drives are being destroyed

#19

Post by willcipriano »

linuxftw wrote: post #14
Gordonjcp wrote: post #5

Earlier quoted context omitted.

Okay, but a single pass of /dev/zero will destroy all the data beyond hope of recovery.

For an actual HDD, maybe that would work. For any solid state drive, it would definitely not work. SSDs and similar spread writes across pools of blocks for 'endurance', so a 1TB drive might actually have 2TB worth of flash on it.

With ssds you only have to wipe the internal encryption key.

Re: Millions of usable hard drives are being destroyed

#20

Post by SkyPuncher »

Gordonjcp wrote: post #5
ReactiveJelly wrote: post #4

Defense in depth is the reason.

Okay, but a single pass of /dev/zero will destroy all the data beyond hope of recovery.

Not true at all. It’s ultimately very complex and device specific, which is why destruction is recommended.
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