Study: 78% of Resold Drives Still Contain Readable Personal or Business Data (consumerist.com)

itwbennett writes: Blancco Technology Group, which specializes in data erasure, bought 200 secondhand PC storage drives (PDF) from eBay and Craigslist to see if they could recover any of the old data saved inside. Their findings: 78 percent of the drives contained residual data that could be recovered, 67 percent still held personal files, such as photos with location indicators, resumes and financial data, and 11 percent of the drives also contained company data, such as emails, spreadsheets and customer information. Only 10 percent had all the data securely wiped, Blancco said. The Consumerist points out that Blancco makes their money from promising secure data erasure, so the company has a "strong and vested interest in these results." As for why so many of the drives contain unwanted information, the report says it has to do with the difference between "deleting" data and "erasing" data. Your files aren't actually deleted when you drag them to the Trash or Recycle Bin, or by using the delete key -- shocking, I know. You can format a drive to erase the data, but you have to be careful of the format commands being used. A quick format, which was used on 40% of the drives in the sample, still leaves some residual data on the drive for someone to possibly access. A full format, which was used on 14% of the drives, will do a better job in removing unwanted files, but it too may still miss some crucial information. The solution Blancco recommends: buy a tool to perform complete data erasure.

Comments

Simple under linux

[Anonymous Coward]

dd if=/dev/zero of=/dev:sdb

or for the paranoid

dd if=/dev/urandom of=/dev/sdb

Why buy an expensive product when a simple one-liner will do the same job

Re:Simple under linux

[gweihir]

Was about to post that. For a nice progress indicator, use

dd_rescue -w /dev/zero /dev/target

Apparently, a single zero-overwrite is entirely enough for modern disks (say, newer than 15 years or so), as these are used close enough to the surface data density limit that even magnetic force microscopy can recover a few scattered bits at best after a zero-wipe.

I think the main problem here is that to do something like this under Windows, you have to jump through some hoops. And the other main problem is (of course) that people do not understand how disk storage works in the first place.

Don't have to buy one

[TheReaperD]

You don't have to buy a secure hard drive erasure tool, DBAN does a reliable job for most drives and is free. SSDs are a new kink in the mix that means that some really advanced tools could retrieve data from the drives, even after a complete wipe but, if you're going up against people that dedicated, I recommend a sledgehammer instead.

Why?

[Calydor]

Why do people even sell old hard drives, let alone BUY used drives that may be full of bad sectors or viruses?

Re:Encrypt your drives.

[MartinG]

> You know the cheapest and most secure way to delete your data is to hit the disk a few times with a slegehammer.

I find that don't make as much on ebay once I've done that.