Disk scrubbing utility ....

Disk scrubbing utility ....

Post by Debbie Key » Fri, 18 Feb 1994 02:42:13



Hello -

Sorry to bother everyone, but ....

I'm looking for a disk scrubbing utility (I need to return a loaner
system and, in addition to removing my files, I want them "scrubbed"
from the disk).

Before writing such a utility, I thought I'd check to see if anyone already
has such a utility written (preferable one the writes random patterns,
rather than just 1s or 0s).


suitable or know where I could ftp such a beast from.

Thanks,
Debbie
--

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Disk scrubbing utility ....

Post by Debbie Key » Fri, 18 Feb 1994 05:21:25


Hello -

Sorry to bother everyone, but ....

I don't usually follow up to my own posts, but a reply that I
received made me realize that I hadn't been completely clear
on what I was looking for ....

I'm looking for a disk scrubbing utility (I need to return a loaner
system and, in addition to removing my files, I want them "scrubbed"
from the disk).

I want to retain the OS files and filesystem info, just scrubbing
out *really* well what's been removed (personal files, programs
written locally, etc).

Before writing such a utility, I thought I'd check to see if anyone already
has such a utility written (preferable one the writes random patterns,
rather than just 1s or 0s).


suitable or know where I could ftp such a beast from.

Thanks,
Debbie
--

| Applied Research Laboratories          |          +1 512 835 3367 w          |
| The University of Texas at Austin      |                                     |
| P.O. Box 8029, Austin, TX 78713-8029   |                                     |

 
 
 

Disk scrubbing utility ....

Post by maenne » Wed, 23 Feb 1994 12:52:33


: I'm looking for a disk scrubbing utility (I need to return a loaner
: system and, in addition to removing my files, I want them "scrubbed"
: from the disk).

: I want to retain the OS files and filesystem info, just scrubbing
: out *really* well what's been removed (personal files, programs
: written locally, etc).

If you want really quick and cheap, (and not guaranteed-- but I've done
it myself), try the following:
1)  delete all files you want deleted
2)  cat > scrub1     <a series of spaces followed by RET ^d>
23  cat scrub1 >> scrub2
4)  cat scrub2 >> scrub1
5)  repeat 3), 4) until you get something like "disk full"; it should
      take not too many repititions since the file size grows exponentially.
6) rm scrub1 scrub2
7) repeat with _ underscores instead of spaces if you like
8) repeat repeatedly until you feel confident

This should overwrite your whole disk with garbage.

Paul

 
 
 

Disk scrubbing utility ....

Post by T.M. Speig » Thu, 24 Feb 1994 20:26:00



   : I'm looking for a disk scrubbing utility (I need to return a loaner
   : system and, in addition to removing my files, I want them "scrubbed"
   : from the disk).

   : I want to retain the OS files and filesystem info, just scrubbing
   : out *really* well what's been removed (personal files, programs
   : written locally, etc).

   If you want really quick and cheap, (and not guaranteed-- but I've done
   it myself), try the following:
   1)  delete all files you want deleted
   2)  cat > scrub1     <a series of spaces followed by RET ^d>
   23  cat scrub1 >> scrub2
   4)  cat scrub2 >> scrub1
   5)  repeat 3), 4) until you get something like "disk full"; it should
         take not too many repititions since the file size grows exponentially.
   6) rm scrub1 scrub2
   7) repeat with _ underscores instead of spaces if you like
   8) repeat repeatedly until you feel confident

It may be a concern to overwrite the inode area on the disk, as well,
if you want to remove *all* possible information (remember, in
communications, the mere fact that a message has been transmitted is
often of value in itself), so make a temporary directory, and fill the
disk with zero-length files (use touch(1)).

Also, remember each directory is a file, and after the files have been
deleted, there may still be traces of their directory entries. To
overwrite these:

1) make a temporary directory on the disk
2) fill it with zero-length entries (using touch again) until its
length is at least the disk's block size. Use names that are found
nowhere else on the disk, perhaps uniq_001, uniq_002, etc. (You may
want to check beforehand, with find(1), that the names are, in fact,
unique across the disk).
3) add the files to each directory entry (use ln tempdir/* target/dir/path), and then
remove them (rm target/dir/path/uniq_*).

Repeat all the operations as many times as your paranoia requires ;-)
All three operations should be quite easy to automate.

Anything I have left out?

--
Toby Speight


 
 
 

Disk scrubbing utility ....

Post by Ted Dunni » Thu, 24 Feb 1994 17:15:21



   : I'm looking for a disk scrubbing utility (I need to return a loaner
   : system and, in addition to removing my files, I want them "scrubbed"
   : from the disk).

   If you want really quick and cheap, (and not guaranteed-- but I've done
   it myself), try the following:
   1)  delete all files you want deleted
   2)  cat > scrub1     <a series of spaces followed by RET ^d>
   23  cat scrub1 >> scrub2
   4)  cat scrub2 >> scrub1
   5)  repeat 3), 4) until you get something like "disk full"; it should
         take not too many repititions since the file size grows exponentially.
   6) rm scrub1 scrub2
   7) repeat with _ underscores instead of spaces if you like
   8) repeat repeatedly until you feel confident

heavens... why not just

cat /dev/zero >x

?

 
 
 

Disk scrubbing utility ....

Post by Gerardo Bentanc » Sun, 27 Feb 1994 14:19:57





>   : I'm looking for a disk scrubbing utility (I need to return a loaner
>   : system and, in addition to removing my files, I want them "scrubbed"
>   : from the disk).
>   If you want really quick and cheap, (and not guaranteed-- but I've done
>   it myself), try the following:
>   1)  delete all files you want deleted
>   2)  cat > scrub1     <a series of spaces followed by RET ^d>
>   23  cat scrub1 >> scrub2
>   4)  cat scrub2 >> scrub1
>   5)  repeat 3), 4) until you get something like "disk full"; it should
>     take not too many repititions since the file size grows exponentially.
>   6) rm scrub1 scrub2
>   7) repeat with _ underscores instead of spaces if you like
>   8) repeat repeatedly until you feel confident
>heavens... why not just
>cat /dev/zero >x
>?

Good idea... aparently not good enough for US government security purposes
tho.. I read somewhere (please verify if you know what I'm talking about :)
that old procedures for erasing sensitive magnetic media involved filling the
disk with 1's (bits not ints) and then 0's.. and then random 1's and 0's..
aparently this wasn't secure enough so the current standard is just plain
and simple destruction of the disk.. that'll fix it :)

regards,
Gerardo Bentancor