Security Basics mailing list archives
Re: Hard Drive data security
From: Ansgar -59cobalt- Wiechers <bugtraq () planetcobalt net>
Date: Thu, 7 Oct 2004 11:27:00 +0200
On 2004-10-05 Paris E. Stone wrote:
I was informed that /dev/null just wrote zeros to the drive and that a better way was multiple passes using random: dd if=/dev/urandom of=/dev/had
You were informed wrong (or at least incomplete). A single pass with zeroes is definitely sufficient if you are addressing data-recovery software. I have yet to hear from any software-based attack that was able to uncover any data from a wiped drive, even after wiping with zeroes in a single pass. If you want to address low-level attacks (like MFM or something): feed the drive to a shredder. /dev/null BTW doesn't write anything. It takes any input and discards it. /dev/zero ist the device you read zeroes from. It makes no real difference whether you use /dev/zero or /dev/urandom, both of them will do the trick.
or maybe /dev/random
No need to waste real randomness for overwriting a drive. Regards Ansgar Wiechers -- "Those who would give up liberty for a little temporary safety deserve neither liberty nor safety, and will lose both." --Benjamin Franklin
Current thread:
- Re: Hard Drive data security, (continued)
- Re: Hard Drive data security xyberpix (Oct 04)
- RE: Hard Drive data security Kristján Hreinn Bergsson (Oct 05)
- RE: Hard Drive data security xyberpix (Oct 05)
- Re: Hard Drive data security Ansgar -59cobalt- Wiechers (Oct 06)
- Re: Hard Drive data security Atom 'Smasher' (Oct 07)
- RE: Hard Drive data security xyberpix (Oct 05)
- Auditing a Win2K box xyberpix (Oct 07)
- Re: Auditing a Win2K box Marco Bellini (Oct 07)
- Re: Auditing a Win2K box Josh Mills (Oct 07)
- RE: Hard Drive data security Paris E. Stone (Oct 06)
- RE: Hard Drive data security Atom 'Smasher' (Oct 07)
- Re: Hard Drive data security Ansgar -59cobalt- Wiechers (Oct 07)
- Re: Hard Drive data security tony tony (Oct 12)
- RE: Hard Drive data security David Gillett (Oct 13)
- RE: Hard Drive data security D. Weiss (Oct 14)
- Re: Hard Drive data security Kirk Schafer (Oct 15)
- Re: Hard Drive data security Ghaith Nasrawi (Oct 15)
- RE: Hard Drive data security ssaehrig (Oct 15)
- Re: Hard Drive data security GuidoZ (Oct 15)
- Re: Hard Drive data security GuidoZ (Oct 15)
- RE: Hard Drive data security Chris Carter (Oct 18)
- Re: Hard Drive data security (slightly OT) Kirk Schafer (Oct 19)