[ale] Need an iso to wipe hard drives.

[Greg Freemyer]

On Fri, Apr 16, 2010 at 10:58 AM, Chris Fowler
<cfowler at outpostsentinel.com> wrote:
> On Fri, 2010-04-16 at 10:07 -0400, krwatson at cc.gatech.edu wrote:
>
>> Darik's Boot and Nuke ("DBAN")
>> http://www.dban.org/
>>
>> DBAN will not wipe sectors that have been reallocated however, Secure Erase will. This only works on IDE and SATA dirves.
>> http://cmrr.ucsd.edu/people/Hughes/SecureErase.shtml
>
> now this brings up an good topic for this list.
>
> Here is how I've done it in the past from bash
>
>
> rm stuff_to_delete
> dd if=/dev/urandom of=/tmp/file;rm /tmp/file
> dd if=/dev/urandom of=/tmp/file;rm /tmp/file
> dd if=/dev/urandom of=/tmp/file;rm /tmp/file
>
> Now the idea is that we first delete the stuff then we fill up disk with
> random crap.  dd will error when we've ran out of space and rm will
> remove the file.  We do this 3 times.
>
> Not sure if this is good idea or not?
>
> I've got a cronjob on my desktop that creates a 4G file of urandom every
> night around 1AM and then deletes it.  Anything I've deleted during the
> day should be blown away at night.

NIST has a sanitation paper that says disk drives of 20GB or larger
capacity are not recoverable even via laboratory means after a single
wipe with zero's.

So your just wasting cpu cycles using /dev/urandom.  Just use
/dev/zero.  And just do it once.

Also, ext2/3 reserves x% of the drive for root, so if your doing the
above as a normal user, your missing that x%.  I think x% is 5%, but I
don't recall for sure.  And 5% of 1TB is 50GB, so it is a big deal.

Greg