Re: dd for windows and imaging a 40Gb drive

[Paul daSilva <pdasilva () polr org>]

Murad,

Imaging a disk to another disk: just be sure the target is empty -- dd 
copies all data block for block, including partition layout and format 
type.  The end result will be a 100% drive image, meaning you could take 
that target drive and boot it on another machine, assuming all the 
hardware was exactly the same.

Imaging a disk to a file, the output will be a raw format file which 
could then be analyzed with forensics applications that accept an image 
file as input.

Imaging a partition to another partition, just be sure the target 
partition is equal or larger in size.  Again, dd will write over the 
target partition, laying down a block by block copy of the source 
partition including partition type.

Imaging (copying) a file to another file, the output will be an exact 
copy of that file, and dd would expect to find a target path that can be 
written to (meaning an existing partition and directory).  I don't 
believe it would care about the target partition format.  For example 
dd.exe for Windows dumping to a Linux server using netcat, taking input 
from NTFS and copying that file on to an EXT3 partition.

Please note that I have never used dd.exe for Windows, so my statements 
above relate to dd for Unix.  Be careful, as dd.exe for Windows has 
slightly different syntax and path definitions.

Also, be careful!  Improper use of dd can destroy/delete your data!



Murad Talukdar wrote:
> Great stuff Paul-thanks for the link to the garner page. I had found the dd
> for windows and was trying to work out whether I could somehow load that
> into a livecd for similar purposes(even just for backing up).
>
> One thing which I'm trying to work out is with regards to a pst file which,
> let's say for argument's sake, lives here
> C:\documents and settings\username\local settings\application
> data\microsoft\outlook\outlook.pst
>
> With the whole windows directory notation being expressed as unix-style
> notation issue(thanks for the clarification) would that mean that if just a
> file or folder needed to be copied, would it correspond to something similar
> to :
> /dev/hda1/documents and settings/username/local settings/application
> data/microsoft/outlook/outlook.pst
>
> I'm going to try it on a test machine and see if this is the case or not.
>
> One other question too-does the empty target disk need to be formatted as an
> ntfs disk before the copy? Or would something that had been an ext2 disk be
> fine?
> -----Original Message-----
> From: Paul daSilva [mailto:pdasilva () polr org] 
> Sent: Friday, December 08, 2006 1:23 AM
> To: Murad Talukdar; security-basics () securityfocus com
> Subject: Re: dd for windows and imaging a 40Gb drive
>
> Murad,
>
> The option is up to you and your needs.  Booting the Windows machine 
> from a Linux LiveCD will give you the ability to snapshot the entire 
> partition or hard drive as a point in time reference, with no 
> 'intereference' - meaning no changes to the filesystem as you capture 
> its image.
>
> You could try to copy the files you need while booted into Windows, 
> copying the desired .pst file over the network.  I'm not sure if this 
> will work when the file is in use (opened under Outlook or whatever by 
> that user), but you can give it a try.  Also, there is a dd for Windows 
> which may have slightly different capabilities than the original dd, 
> like dumping data from a live file system?  I'm not sure, but you can 
> check it out -- they do use slightly different conventions with respect 
> to drives and partitions.  Here are some links:
>
> http://www.chrysocome.net/dd
> http://users.erols.com/gmgarner/forensics/
>
> Lastly, yes, if you book from a Linux Live CD, your disks and partitions 
> will assume that naming convention:
>
> /dev/hda    primary hard drive
> /dev/hdb   secondary drive on the primary IDE
> /dev/hdc    first drive on secondary IDE
> /dev/hdd   secondary drive on secondary IDE
>
> /dev/hda1   first partition on primary drive
> and so on....
>
> Cheers,
> Paul
>
>
> Murad Talukdar wrote:
>   
> > Thanks Paul,
> > Now the source machine in question is a winxp box so I take it that
> >     
> running
>   
> > dd and piping to nc would mean booting to a live cd(on source machine) in
> > order to prevent any 'interference' with the data?
> > Now I'm assuming that when running a live cd (knoppix std or FIRE eg) will
> > mean that the main partition should show up as /dev/had or similar even
> > though it is a windows box. Is that right?
> > What I really need is a copy of this user's pst files for legal to check
> >     
> for
>   
> > 'incriminating' (ie non-criminal) emails but I did suggest to them that
> > taking an image of the drive first, for possible later use may be
> >     
> advisable.
>   
> > Now I'm not a forensic expert and I did say that normally this should be
> > done by such but they have said that it really is just a preliminary
> > investigation. <shrug>
> > -----Original Message-----
> > From: Paul daSilva [mailto:pdasilva () polr org] 
> > Sent: Thursday, December 07, 2006 8:47 AM
> > To: Murad Talukdar
> > Cc: security-basics () securityfocus com
> > Subject: Re: dd for windows and imaging a 40Gb drive
> >
> > Murad,
> >
> > I can't answer how long the process will take, as far too many factors 
> > are involved.
> > However, to use dd over the network, you could consider piping its 
> > output to netcat.
> >
> > On the Target system, where image will be dumped to, run:
> > nc -l -p 9000 | dd of=/path/image-file.dd (or of=/dev/hda)
> >
> > On the Source system to be imaged, run:
> > dd if=/dev/hda | nc 192.168.1.120 9000
> >
> > Be sure to edit the Target system output file of=, as it can be a file 
> > or you can dd to another disk or partition (clone).
> >
> > Be sure to edit the Source system input file if= (right drive device and 
> > partition number), and use the right IP address and port number for the 
> > Target system). Googling "dd and netcat" will give you lots more 
> > information on this topic.
> >
> > Cheers,
> > Paul
> >
> >
> >
> > Murad Talukdar wrote:
> >   
> >     
> > > Hi all,
> > > I need to estimate how long it would take to image a 40gb drive with a
> > > single partition on it using dd. (I guess this is more dependant on write
> > > speeds and throughput than anything else)
> > > Also, what would be the syntax of the output file be if I were to image
> > > across the network? Or can dd be used by using a crossover cable and
> > >     
> > >       
> > mapping
> >   
> >     
> > > drives first?
> > > But, if I were to map a drive to the machine in question, does that
> > > 'interfere' with the drive in any way? 
> > > I'm planning to use dd for windows-which I can get to work fine for
> > > files/folders on my local machine but am struggling over the network
> > >     
> > >       
> > because
> >   
> >     
> > > I'm not sure of the syntax. 
> > > No man dd on windows.
> > >  
> > >
> > >
> > >
> > >
> > >     
> > >       
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>   


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