Using dd cmd to copy drive.

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    • #5079
      Ash Chole

      K so this is going to be a bit off cause is special situation. I am trying to fix labs for my Forensics class. Here is the situation.

      We are using a VMware LabManager with a Linux box and a XP box.
      The lab is suppose to use a external drive but we are not able to do that.
      There is a Z: drive that has sharing set up on it. I have used Prodiscover Basic to save the data on the Z:.

      On the linux box I have mapped the /share dir to the Z:.

      This is where it gets a little off. I am not able to copy the entire Z: with the dd cmd.
      dd if=/share | split -b 20m – test

      I have to go in and specify the individual file.
      dd if=/share/Greek/test | split -b 20m – test

      As you can imagine this would be hectic if we need to copy an entire drive.

      I think I provided all the pertinent info. If not, feel free to ask!

      Any ideas?

    • #32238


      First, I would use DCFLDD.  It supports many features that DD doesn’t. 

      Why are you trying to DD a mapped drive?  You are not getting any slack space or deleted data this way.  Why not just DD the physical drive in either Windows or Linux.  (DCFLDD has been ported to Windows). 

      If you are doing a DD image of a directory, you would have to write a script to recreate the directory structure and to DD every file. 

    • #32239

      The dd command is not what you need in this instance.  dd is used for making exact images of drives or partitions.  The if= switch takes a FILE as its argument.  This is typically the file Linux associates with a partition or drive, such as /dev/hda1.  It sounds like you’re trying to copy data over a network.  If you just want to copy data, why not use cp?  If you need to keep files synchronized over a network share, lookup rsync. 

      If you are trying to make an image of a drive to use for forensic purposes, your current setup simply won’t work for this purpose.  Simply by mounting a drive you could make change to it which makes your image invalid.  If the drive is in Windows, then shared, then mounted in Linux, then copied… this isn’t how you do forensics, so I’m going to assume that’s not what you’re trying to do.

    • #32240

      There are situations where using DCFLDD to copy individual files over the network may not be a bad idea.  Here is why.

      1.  You can specify a block size and it is possible to achieve a faster copy performance with larger files. 
      2.  You can have a log file of each files source and destination hash value.  This is of course is huge in forensics.
      3.  You can preserve MAC times. 

      Sometimes you do not have an option to do a proper image of a physical device.  This can be the case when you are working with large NAS appliances, busy network servers that cannot be taken down, etc.  You best option may be to do a logical image or a live image.  Live images have their own issues, like bit-shifting.  A live image may not work for a large NAS.

      Having said this, there are much better tools that will let you accomplish the same thing.  EnCase in acquisition mode, can create L01 images (Logical Images of a folder).  FTK Imager is free and can also create folder images (ad1). 

    • #32241
      Ash Chole

      We are using Vcenter Lab Manager and are limited to what we have on it. The lab itself calls for the students to use the dd cmd. It discusses DCFLDD but is to in use for this lab.

      We finally decided to just go with adding another drive on the same machine to simply allow us to transfer the file and do a md5 ckecksum to make sure they were not “touched” by the move.

      I finished the step by step instructions last night.

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