5 ms·
Delete all the files then "dd" from the random device until the drive is full? Must we always jump straight to the hydraulic press?
by 13of40 4y ago
Delete all the files then "dd" from the random device until the drive is full? Must we always jump straight to the hydraulic press?
- bcoates 4y agoAs mentioned in the article, that's not reliable. Drives have lots of overprovision blocks and there's no way of consistently forcing them to be used; and drives might mark blocks as too questionable/worn to reuse and never reset them. Also a standard failure mode of SSDs is refusing to accept writes, so you'll have to handle that case.
- georgyo 4y agoEncryption plus a single rewrite is likely many times more sufficient than ever needed. Even if there is a massive 10% block reserve, you looking at a random 10% of an entire encrypted drive. Figuring out how to just decrypt those blocks is a very hard challenge, then figuring out the SSD block mapping is going to be very challenging, and then for a chance to maybe get something valuable from that 10%. Multiple very difficult challenges for only a chance of maybe recovering something useful. Related, I just had a hard drive head crash. I was able to use dd_rescue to read out 40% of the drive before it fully gave out. It's amazing, but at least NTFS stores data everywhere. I recovered a few small plain text file, but not a single image was recoverable. It was pretty shocking to me.
- LinuxBender 4y agoMust we always jump straight to the hydraulic press? Not always. I suppose it depends on your information security case. If your goal is to secure your kids laptop from the average thief that is heading to the pawn shop, maybe "secure erase" of encrypted drives may be sufficient. If on the other hand one is protecting intellectual property, customer data and so on, then perhaps that average thief was hired by someone with significant resources. I would wager that a percentage of the people reading this comment are using a work laptop and have some IP on their drive that in the wrong hands could cost billions. Even some of the emails I've seen could do significant damages.
- throw0101a 4y ago> the random device /dev/zero would be sufficient. Also easier to confirm things worked (if desired) since you know what to expect on read-back.
- jusssi 4y agoYou're assuming the drive doesn't do something smart when it detects it's being filled with zeroes. It could at least in theory decide to do the same thing it does when you TRIM a sector.
- lazide 4y agoI suspect it won’t be long (if it isn’t already the case) that defacto run-length encoding is built into SSD firmware. Write 5 gig of zeros? OK! You just got more drive reserve capacity!
- bombcar 4y agoHydraulic press is too obscure, .45 ACP works just as well. But it depends on your risk profile, for most people a wipe-and-reuse is going to be fine, especially if the "reuser" is already a trusted entity.
- amalcon 4y agoA firearm is a silly tool for this. A hammer (optionally combined with good nails) can do substantially the same thing to all relevant materials (aluminum, glass, ceramic, silicon, plastic), but cheaper and more safely.
- LinuxBender 4y agoI suppose if one could obliterate most of the chips with 3 or 4 well placed shots then your solution is certainly more cost effective than mine should one not have a future use for a press. This sounds like a video idea for DemolitionRanch.
- adql 4y agoI guess used microwave would be easiest and cheapest option for SSDs
- bombcar 4y agoA microwave may not even damage the chips internals; you'd have to actually test and verify it.
- 4y ago