How do I wipe a modern SSD to prevent data recovery?

User_already_exist@lemmy.world to Asklemmy@lemmy.ml – 111 points –

I understand traditional methods don’t work with modern SSD, anyone knows any good way to do it?

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Physical destruction. It's the only way to be 100% sure.

For secure data destruction, either pay for it to be done properly, or create your own way of doing it. A decent sized drill bit can do all the work for you, at the cost of a new drive of course.

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If it's really an issue where "if the data on this SSD falls into the wrong hands, lives will be ruined" sort of thing, my favorite data security tool for this job is a bench grinder. Difficult to put the data back together when the flash chips are powder scattered throughout 14 different shop surfaces and at least two lungs.

I prefer thermite. Recover my data from a messy contaminated slag heap.

A special feature known as SSD secure erase. The easiest OS-independent way is probably via CMOS setup – modern BIOSes can send secure erase to NVM Express SSDs and possibly SATA SSDs.

Did this already, it took 1 second for a 2TB drive. Would you trust that?

Most SSD/flash secure erase methods involve the storage having full disk encryption enabled, and simply destroying the encryption key. Without the encryption key the data can't be deciphered even with the correct password, as the password was only used to encrypt the encryption key itself. This is why you can "factory reset" an iPhone or Android in seconds.

It is the only approved method for data destruction for the several banks and government agencies I support. If they trust it, I trust it.

I have checked a couple of times out of curiosity, after a secure erase the drive is as clean as if it had been DBANed. Sometimes things are standards because they work properly.

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Encrypted volume and burn the encryption key

That's better for prevention than after the fact for the wear leveling reasons others have mentioned.

Call the devices secure erase functionality.

here’s how to do it to sata and pata devices

I don’t do some of the checking and testing in that article, I just do —security-erase-enhanced and unless it fails it’s fine.

You could also encrypt the contents and delete the key.

This is the correct answer. Due to wear levelling, a traditional drive wipe program isn't going to work reliably, whereas most (all?) SSDs have some sort of secure erase function.

It's been a while since I read up on it but I think it works due to the drive encrypting everything that's written to it, though you wouldn't know it's happening. When you call the secure erase function it just forgets the key and cycles in a new one, rendering everything previously written to it irrecoverable. The bonus is that it's an incredibly quick operation.

Failing that, smash it to bits.

And if you're hiding from a nation state ... don't trust that, smash it to bits and dispose of them at different trash collection locations 🙂

For all average user requirements that just involve backups, PII docs, your sex vids, etc (e.g. not someone who could be persecuted, prosecuted, or murdered for their data) your best bet (other than physical destruction) is to encrypt every usable bit in the drive.

  1. Download veracrypt
  2. Format the SSD as exFAT
  3. Create a new veracrypt volume on the mounted exFat partition that uses 100% of available space (any format).
  4. open up a notepad and type out a long random ass throwaway password e.g. $-963,;@82??/@;!3?$.&$-,fysnvefeianbsTak62064$@/lsjgegelwidvwggagabanskhbwugVg, copy it, and close/delete without saving.
  5. paste that password for the new veracrypt volume, and follow the prompts until it starts encrypting your SSD. It'll take a while as it encrypts every available bit one-by-one.

Even if veracrypt hits a free space error at the end of the task, the job is done. Maybe not 100%, but 99.99+% of space on the SSD is overwritten with indecipherable gibberish. Maybe advanced forensics could recover some bits, but a) why the fuck would they go to that effort for a filthy commoner like yourself, and b) what are the chances that 0.01% of recoverable data contains anything useful!?! You don't really need to bother destroying the header encryption key (as apple and android products do when you wipe a device) as you don't know the password and there isn't a chance in hell you or anyone else is gonna guess, nor brute force, it.

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Are you considering using the drive afterwards? Because “toss it in a microwave for like 5 minutes” is always a valid answer if you’re not worried about reusing it.

Presumably there's a risk of damaging the microwave?

If you want to cook with it yeah, but if it's a junk toy then it's practically indestructible

  • Secure erase using the drive OEMs tool.
  • If you were using something like bitlocker then simply dump the key.
  • Wood chipper or some other form of absolute physical destruction.
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This article covers several methods. Personally, I'd look for a BIOS based tool first, as that would be free and easiest. After that, the Diskpart Clean All command is probably fine for anything other than Top Secret data which a government based threat actor would be willing to put a lot of resources into recovering. If it's just your tax documents and porn archive, no one is going to care enough to dig out anything which that command might have left behind.

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i know this isn't what is being asked, but disk level encryption is cool

NSA requires the use of a industrial shredder that can grind the components into pieces less than 2mm.

https://ameri-shred.com/portfolio-items/2mm-ssd-solid-state-drive-hammer-mills/

If you can't do that, you should incinerate the drive at over 700 degrees.

As far as wiping goes, a 3 pass overwrite alternating 0s and 1s is good enough as long as it's done over the entire drive, not just the partition.

BCWipe is good enough for this

doesn't just overwriting the data work?

No. Modern SSDs are quite sophisticated in how they handle wear leveling and are, for the most part, black boxes.

SSDs maintain a mapping of logical blocks (what your OS sees) to physical blocks (where the data is physically stored on the flash chips). For instance, when your computer writes to the logical block address 100, the SSD might map that to a physical block address of 200 (this is a very simplified). If you overwrite logical block address 100 again, the SSD might write to physical block address 300 and remap it, while not touching the data at physical block address 200. This let's you avoid wearing out a particular part of the flash memory and instead spread the load out. It also means that someone could potentially rip the flash chips off the SSD, read them directly, and see data you thought was overwritten.

You can't just overwrite the entire SSD either because most SSDs overprovision, e.g. physically have more storage than they report. This is for wear leveling and increased life span of the SSD. If you overwrite the entire SSD, there may be physical flash that was not being overwritten. You can try overwriting the drive multiple times, but because SSDs are black boxes, you can't be 100% sure how it handles wear leveling and that all the data was actually overwritten.

No, "overwritten" data doesn't actually get erased right away due to wear levelling. As SSDs get esoterically smart with how they prevent unnecessary erase operations, there's no way to be sure without secure erase.

overwriting the whole drive would fix that

Smash it to pieces, melt it down into a blob and drop it down a borehole at the nearest quarry

Install all your steam library to full your SSD. Should do the job. Empty the disk, rinse and repeat a few times.

Crack it open and run s drill through the center of each flash chip.

If it is a large concern, then encryption will help. There are even drives with built-in encryption exactly for this purpose.

Otherwise, will with non-repeated data. Repeat 9 times. (A heuristic, based on something I read 10 years ago.)

Do not use repeated digits. Those are optimized out.

Fill the drive 100% using data duplicator then delete everything on the drive. Repeat a few times to ensure you scrub all blocks. There is no need to physically destroy the drive.

edit: fair criticism of this approach in cases when the data is unencryptd and the hard drives has bad blocks. I just wanted to give a counter to the destroying hardware approach which isn't necessary warranted

That doesn’t work with SSDs anymore. Their controllers map “bad” blocks which are put in an RO state and writes no longer go there but data still exists. There is usually a buffer of extra space so you do see the capacity loss, but if you bypass the controller you can still read the data there.

That's fair, I can appreciate an attack vector in cases where there are bad blocks and the drive was unencrypted. Luckily bad blocks are less common with modern SSDs and assuming the disk was encrypted, a few bad blocks are unlikely to expose any contents. So knowing the number of bad blocks and what data was stored would inform if a fill and empty approach would be suitable to sanitize the drive.