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RE: Copying HDDs for forensic purposes?
From: "Sgt. Elias" <sgt.elias () chello se>
Date: Tue, 18 Nov 2003 18:24:48 +0100

Hi Spencer

One important rule when it comes to computer forensic is that never
conduct an examination of the original media, but always use a bit for
bit mirror copy of the original.

When searching through a hard drive while running windows, opening files
may unintentionally modify evidence. Even booting windows results in a
number of files being altered. And because digital data can be so easily
changed, a judge or defense attorney may raise the question of possible
tampering with the original media if it is directley examined and serve
as the only evidence.
To ensure that evidence will be valid and will hold in court you may do
it this way.

Boot the evidence computer with another operating system, such as Linux
or DOS then use a checksum or secure hash (MD5 or SHA-1) applications to
create file and directory signatures. When using DOS or Linux as an
alternate OS it prevents windows to making file changes on start up.
The copy should be made on sterile media new or "wiped" to ensure that
there are no residual data left.

After copying, use the checksum or hash utility to verify that copy is
identical to the original.
And the entire process schuld be well documented and the original
harddrive stored in a secure location.

Then start the work to find whatever you are looking for
Btw A great book is Secrets of Computer Espionage: Tactics and
countermeasures by Joel McNamara. 

www.symantec.com Norton utilities
www.jasc.com Quick view plus

Gl hf


-----Original Message-----
From: Spencer D'oro [mailto:sdoro () comcast net] 
Sent: den 15 november 2003 19:09
To: security-basics () securityfocus com
Subject: Copying HDDs for forensic purposes?

Hello to all,

I am interested in forensic examinations of hard drives.  In the little
material I have seen, the authors state that no examination should be
made of an original device; that instead a copy should be made and all
examinations made to that device.  My question is this:  If you make a
copy of the hard drive, does it copy the sectors that had recently
deleted files or does it just mark them as blank in the partition table
of the new drive? What if the source is physically damaged?  Or do you
need a special utility to get the "erased" data?  Thanks in advance for
the help.


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