Re: Cleaning

[Adam Guyot <aguyot@speakeasy.net>]

On Sat, Sep 15, 2001 at 04:10:23PM +0000, Alex Kirk wrote:
> I'd like to go about cleaning my hard drive, so that my free space is 
> absolutely empty. In other words, I know that even if I delete files from my 
> system, remnants of them are still physically on my drive; I also know that 
> it's possible to clean those off, and that's what I want to do now. 
> 
> I believe this can be done with dd, but I'm not sure how to go about it. Any 
> pointers you can give would be very helpful. 

They are tools to shred/wipe data that is in a file of course. 
A good one is at http://wipe.sourceforge.net.
But wiping files that no longer exist is another matter;
try the following:

http://packetstormsecurity.org/groups/thc/secure_deletion14.tar.gz
(you will want to use the sfill tool from that set)

This article talks a little bit about it.
http://www.thehackerschoice.com/papers/anonymous-unix.html#62

You can use dd as it says but you will still only really fill
99% of the disk w/ dd and won't get it all.

The Coroners Toolkit _could_ help:
http://www.fish.com/tct/

Just take the part of the code that searched for free inodes
and change the read of the data blocks to a write.

Others have mentioned Guttmans article on secure deletion; one can
never really be sure that that data is gone for good ;).

--a