Full Disclosure mailing list archives
Re: Erasing a hard disk easily
From: "morning_wood" <se_cur_ity () hotmail com>
Date: Mon, 12 Jul 2004 18:42:23 -0700
Since that time I have seen sensationalist TV shows showing how FBI and
CIA
operatives get stuff out written to a sector BEFORE the sector was overwritten and I honestly cannot understand how that could be, if at all possible. Am I right in thinking those shows are bull?
simple... by analizing the magnetics of the disk .... one write makes 010101 etc the 0's and 1's are written to the disk by a magnetic manipulation to the disk there is a "level" of magnetisim than can be measured the disk electronics detect this "difference". lets say a "0" can be between .000 and .010 and a "1" is between .996 and 1.00 when you write again over the data, the magnetic properties of the disk "rember" slightly the previous write. now when you analize the disk there is a "ghosting" of the previous data example... new data pits "0" =.009 "1"=.999 ( ghost pits ) "0"=.003 "1"=.997 the drive electronics will detect the higher magnetic "pits" as actual data and discard the data below the new threshold. recovering the "ghost" data is now trivial by setting the thresholds below the new data levels.. logic: discard any data over .004 for "0" and .996 for "1"s this is a very basic example of course but shows how this technique is used. Donnie Werner _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.netsys.com/full-disclosure-charter.html
Current thread:
- Remote crash of Half-Life servers and clients (versions before the 07 July 2004) Luigi Auriemma (Jul 12)
- Erasing a hard disk easily amilabs (Jul 12)
- RE: Erasing a hard disk easily amilabs (Jul 12)
- Re: Erasing a hard disk easily Maarten (Jul 12)
- Re: Erasing a hard disk easily Gregh (Jul 12)
- Re: Erasing a hard disk easily David Vincent (Jul 12)
- Re: Erasing a hard disk easily James Riden (Jul 12)
- Re: Erasing a hard disk easily Michael Williamson (Jul 12)
- Re: Erasing a hard disk easily Dave Horsfall (Jul 12)
- Re: Erasing a hard disk easily morning_wood (Jul 12)
- RE: Erasing a hard disk easily amilabs (Jul 12)
- Re: Erasing a hard disk easily Thomas Sjögren (Jul 12)
- Re: Erasing a hard disk easily Tim (Jul 12)
- Re: Erasing a hard disk easily Aditya, ALD [ Aditya Lalit Deshmukh ] (Jul 12)
- Re: Erasing a hard disk easily Pavel Kankovsky (Jul 13)
- Erasing a hard disk easily amilabs (Jul 12)
- Re: Erasing a hard disk easily Valdis . Kletnieks (Jul 14)
- RE: Erasing a hard disk easily Todd Towles (Jul 14)
- Re: Erasing a hard disk easily Joel R. Helgeson (Jul 14)
- Re: Erasing a hard disk easily Valdis . Kletnieks (Jul 16)
- Re: Erasing a hard disk easily Jeff Kell (Jul 12)