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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

#131

Post by netsharc »

kryogen1c wrote: post #54
NotYourLawyer wrote: post #28

> The irony is that shredding devices is relatively risky today. The latest drives have 500,000 tracks of data per square inch. A sophisticated data recovery person could take a piece as small as 3mm and read the data off it, Mr Hands says. I call bullshit on this, unless you can show me a single example of this ever happening anywhere.

Don't forget that sensitive data is encrypted. The only thing harder than breaking bitlocker on a hard drive is breaking bitlocker on a random 0.5% chunk of hard drive unaligned with the r/w tracks. Bullshit is too weak a word.

Don't HDD's come with encryption per default nowadays? I.e. the 1's and 0's on the platter go through a layer of decryption that happens on the logic board of disk, before it travels through the SATA cable. And vice-versa when writing.

There's an ATA command to protect the encryption key with a password (and you'll be asked on boot for the password), but if the password isn't set, there's still an encryption key. Just make that irretrievable and the information is theoretically irretrievable.

But yeah, funny how superstitions still control the world and people still say "The HDD needs to be shredded so we're absolutely sure!"

Re: Millions of usable hard drives are being destroyed

#132

Post by rhn_mk1 »

Gordonjcp wrote: post #70
rhn_mk1 wrote: post #30

Earlier quoted context omitted.

Will it though? What if you had some bad sectors which became unwriteable and now contain sensitive data forever?

They won't be readable either, if they're that bad.

Even if not all bits can be error corrected successfully, surely there's enough correct bits remaining to recover some secrets.

A 512-byte sector with 100 bytes stuck is "unreadable", but I wouldn't want my secrets to be read out in some raw mode from the 412 good bytes.

Re: Millions of usable hard drives are being destroyed

#133

Post by unaindz »

JohnFen wrote: post #82
Gordonjcp wrote: post #62

Earlier quoted context omitted.

Why do you think it doesn't work as well as you'd think?

A read/write head does not follow precisely the same path every time. It has a positioning error that makes subsequent reads/writes take place slightly offset from earlier ones. With the proper equipment and expertise (and helped out by the error correction mechanisms), you can recover a substantial amount of data that has been "overwritten" on an existing track. This is why "data shredding" applications erase the ol…

That's theoretical only. Nobody has ever demonstrated that since the theory started and now hdd complexity and density has increased dramatically.

Re: Millions of usable hard drives are being destroyed

#134

Post by SkyPuncher »

paulmd wrote: post #120
SkyPuncher wrote: post #96

From a risk management perspective, most storage devices have a "table stakes" requirement to "not lose data". Performance, storage duration, reliability, etc, etc, etc, etc, are all secondary to "do not lose data". You're dead in the water if you lose data. Everything beyond "don't lose data" can and is proprietary implementations of read/write; often with tricks being used to increase speed. While it's challenging…

> For example, I believe many SSDs will simply mark a block as "unused" rather than physically rewriting the data in that block. When the block gets used again, you simply set it to the new values. Most SSDs (everything that follows the OPAL standard) actually encrypt all data all the time, and support a "secure erase" mode that destroys the encryption key from the TPM and renders the data inert. Copy the flash chips…

I understand that. I'm over simplifying some things.

At the end of the day, physically destroying something is clear and easily understandable to absolutely anyone who is put in charge of device disposal. No conditionals, no complex configurations. Take the hard drive out and destroy it.

Re: Millions of usable hard drives are being destroyed

#135

Post by Gordonjcp »

JohnFen wrote: post #82
Gordonjcp wrote: post #62

Earlier quoted context omitted.

Why do you think it doesn't work as well as you'd think?

A read/write head does not follow precisely the same path every time. It has a positioning error that makes subsequent reads/writes take place slightly offset from earlier ones. With the proper equipment and expertise (and helped out by the error correction mechanisms), you can recover a substantial amount of data that has been "overwritten" on an existing track. This is why "data shredding" applications erase the ol…

Okay, but how can you determine what the old value was, given that it's now a random value multiplied by a random value with yet another random value added on top?

Hard disks don't record zeros and ones...

Re: Millions of usable hard drives are being destroyed

#136

Post by JohnFen »

Gordonjcp wrote: post #135
JohnFen wrote: post #82

Earlier quoted context omitted.

A read/write head does not follow precisely the same path every time. It has a positioning error that makes subsequent reads/writes take place slightly offset from earlier ones. With the proper equipment and expertise (and helped out by the error correction mechanisms), you can recover a substantial amount of data that has been "overwritten" on an existing track. This is why "data shredding" applications erase the ol…

Okay, but how can you determine what the old value was, given that it's now a random value multiplied by a random value with yet another random value added on top? Hard disks don't record zeros and ones...

> but how can you determine what the old value was, given that it's now a random value multiplied by a random value with yet another random value added on top?

It's an extremely difficult problem, and in the best case you won't get a complete copy of old data. That's why this isn't an avenue of attack that you're likely to ever encounter.

This is the sort of thing that would only be considered by very wealthy attackers (governments and corporations), and even then only if they're very certain that the drive contains data of unusually high value.

But it is possible, and has been done, to extract useful data that has been overwritten a single time with zeros.

Re: Millions of usable hard drives are being destroyed

#137

Post by awesomeMilou »

deepsun wrote: post #130
ac29 wrote: post #125

Earlier quoted context omitted.

If I can store drive encryption keys on a HSM in my old, consumer grade laptop, I would hope that large storage systems have at least the same degree of protection.

But if that HSM module or machine suddenly dies, the system would lose all the customer's files. Not good.

If I understand it correctly, the HSM on the HDD dying is about as likely as a HDD PCB failure. Of course in these scenarios you can't just swap the PCB's to recover the data, but in an Enterprise setting you would have mitigated this anyways, by using a form of redundant storage. If you rely on just one drive for your data's continued existence, you're doomed anyways.

[0] https://wiki.archlinux.org/title/Self-encrypting_drives

Re: Millions of usable hard drives are being destroyed

#139

Post by Krisjohn »

crazygringo wrote: post #71

This article mentions disposing of hard drives that have reached their five-year mark and are no longer under warranty. Does anybody actually want hard drives this old? Isn't the whole point that the risk of failure and therefore data loss is too high by this point? Even if you're using them to store data redundantly, you're running the risk that when one drive fails, the backup will also encounter failure due to the…

I work somewhere that specialises in secondhand enterprise equipment and storage. The answer to your first question is "yes, but they really shouldn't". We're burning more hours than we can spare dealing with drive failures. Sure, we have RAID arrays capable of withstanding multiple failures, but we still find ourselves scrambling to replace drives faster than they're failing, even when they were tested before they were put in the spare pile.

Also, fuck Chia. It was supposed to be a low-power "proof of storage", but it's really "proof of prior work" and burns even more energy than proof of work since you need to constantly power the cryptographic calculations AND storage.

Re: Millions of usable hard drives are being destroyed

#140

Post by fomine3 »

kryogen1c wrote: post #54
NotYourLawyer wrote: post #28

> The irony is that shredding devices is relatively risky today. The latest drives have 500,000 tracks of data per square inch. A sophisticated data recovery person could take a piece as small as 3mm and read the data off it, Mr Hands says. I call bullshit on this, unless you can show me a single example of this ever happening anywhere.

Don't forget that sensitive data is encrypted. The only thing harder than breaking bitlocker on a hard drive is breaking bitlocker on a random 0.5% chunk of hard drive unaligned with the r/w tracks. Bullshit is too weak a word.

It's fortunate if every sensitive data are encrypted
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