CentOS - Jan 2013 - wiping out data on a disk (no physical acess to the machine)

Hi,

I need to securely wipe out a disk on a remote machine, but I don't have
access to that machine.
Therefore I cannot use the LiveCD+shred (or dd) combination.
Besides manually shreding known data files, I am wondering if there is a (free)
tool that can be used in my case.
Thanks.

On 01/08/2013 05:06 PM, Yungwei Chen wrote:
> I need to securely wipe out a disk on a remote machine, but I don't
have access to that machine.
> Therefore I cannot use the LiveCD+shred (or dd) combination.
> Besides manually shreding known data files, I am wondering if there is a
(free) tool that can be used in my case.
> Thanks.
I hoping that you mean to physical access but you can make
an ssh connection.  If so, here are the steps.  Note that you'll
need to replace /dev/sdXX with the device of your swap part-
ition and /dev/sdX with the device of the hard drive.  It will
run for several hours and leave you with a blank hard drive.

1)   connect using ssh and stop all services
2)   swapoff /dev/sdXX
3)   shred -n5 -z -v /dev/sdX
4)   echo 1 > /proc/sys/kernel/sysrq
6)   echo o > /proc/sysrq-trigger

c

>> Thanks. Is it possible that shred exit abnormally in any case (for
example,
>> some files that it relies on have been shreded)?
>
> Without physical access to the machine so you can see (and control) what is
> actually going on, there is no way to 100% guarantee that the data is
> completely destroyed.
>
If you had some disk space could you create a partition
and install a minimalistic Linux version, set your
system to boot the minimalistic Linux version, log
in and completely destroy any partition you want and
you could just leave the minimalistic Linux version.

On 01/08/2013 02:06 PM, Yungwei Chen wrote:
> I need to securely wipe out a disk on a remote machine, but I don't
have access to that machine.
> Therefore I cannot use the LiveCD+shred (or dd) combination.
If you have enough RAM to hold the live disk, you can boot the whole 
thing from grub, probably using memdisk.  If you boot a live image with 
memdisk, you can safely wipe the hard disks without the running kernel 
crashing.

On 01/12/2013 04:35 PM, Reindl Harald wrote:
> Usually if no service is running "dd if=/dev/zero
of=/dev/your-sysdisk"
> does crash more or less very late and if you destory the datadisks before
> there is nearly zero chance to recover any data
If I care enough to wipe the disks in a server, "usually" and
"late" is
not going to cut it.  Any attempt by the kernel to read any filesystem 
is likely to cause a panic before wiping is complete.  If you want to 
completely wipe a disk, you need the root filesystem to be somewhere else.