[lug] drive free space "wiper" recommendation

[Paul E Condon]

On 20101009_235617, Sean Brady wrote:
> As a former pc tech, you need to do the best wipe that you can on the entire drive.
> 
> Remember there are hashes stored in different places, and index data combined with predictive heuristic algorithms can recover data you didn't know was sensitive.  Wipe the entire drive with the best gnu tools you can find. A completely wiped drive normally will not void a warranty that is honored on hardware failure.

I'm looking to learn something from reading this list. In this case,
this looks to be sound advice, but ... How can a computer geek who
posts a question like this judge which is the better/best tool? Claims
made at the web site where the tool is offered for download cannot be
simply trusted, IMHO. How does one test a disk wipe to verify that it
has worked correctly?

The recent flurry of reports about stuxnet make me wonder what
fraction of the offerings are actually trojan horses, which try to
report to their masters who has data that they are sufficiently
concerned about that they want to wipe the disk clean?

It seems to me that in the limited situation where there is no reason
to preserve any data on the HD, then dd would do a pretty fair job, or
maybe two passes of dd with ones and zeros. What more could a 'better'
tool offer? (This sounds like a rhetorical question, but I really am
just asking. Security issues puzzle me because there is always the
possibility yet another level of deception.)

Any thoughts? And appologies to Karl for what might seem to be hijacking
his thread. I really intend a somewhat deeper consideration of his
question.

> 
> Besides, what's worth more, your warranty or your identity?
> 
> My two cents. Best of luck to you.
> 
> ----- Reply message -----
> From: "Anthony Foiani" <tkil at scrye.com>
> Date: Sat, Oct 9, 2010 7:43 pm
> Subject: [lug] drive free space "wiper" recommendation
> To: "Boulder (Colorado) Linux Users Group -- General Mailing List" <lug at lug.boulder.co.us>
> 
> karl horlen <horlenkarl at yahoo.com> writes:
> 
> > i need to ship a computer back that's under warranty. i've already
> > moved / deleted the files off of the drive that i deemed sensitive.
> >
> > can anybody recommend a good, free, non spyware based utility to
> > help me "wipe" the free space left by my previous deletes and moves?
> > dban looks like an *entire* drive wipe utility.  i don't want to
> > permanently delete the entire drive, just the unused space.
> >
> > fyi, this is a win xp based system.
> 
> Since this is a Linux-centric list, might I suggest a Linux-based boot CD?
> 
> I haven't tried these, but from a quick google search:
> 
>   http://www.sysresccd.org/System-tools
> 
>     "Secure Deletion
>        Several wiping tools (such as shred and wipe) ensure that files
>        are really erased from the hard disk."
> 
>   http://www.dban.org/
> 
>     "Darik's Boot and Nuke ("DBAN") is a self-contained boot disk that
>     securely wipes the hard disks of most computers. DBAN will
>     automatically and completely delete the contents of any hard disk
>     that it can detect, which makes it an appropriate utility for bulk
>     or emergency data destruction."
> 
> Even something like Fedora Live should have drive-wiping tools, since
> "shred" is a part of coreutils.
> 
> Good luck,
> t.
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-- 
Paul E Condon           
pecondon at mesanetworks.net