Re: I'm having an image problem...

From: James.Holleyat_private
Date: Fri Feb 14 2003 - 19:50:08 PST

  • Next message: Michael Cecil: "Re: I'm having an image problem..."

    James said:
    
    /*
    I took md5 checksums of the images from the CD and subsequently my working 
    
    copies and this was my result ... These checksums match those obtained 
    from the copies on the hard drives,
    */
    
    This seems a bit confusing to me. How do "images from the CD" and "copies 
    on the hard drive" relate to each other?
    
    /*
    The disk is formatted with FAT32 which from my understanding would 
    normally 
    have alternating pages/sectors of 00 and FF not all 00, is this correct?
    */
    
    The file system on a drive and the data on a drive have no direct 
    correlation except for the file system specific data structures that a 
    format process writes to a drive. The normal format process itself does 
    not write to the data area of a drive, so if the drive has any data on it, 
    and you format it, the data can generally be recovered. It would not be 
    accurate to assume that a FAT32 drive should necessarily have alternating 
    \x00 \xFF in free space.
    
    /*
    An analysis of the registry for installed programs shows no third party 
    disk 
    utilities, leaving only stand alone utilities, software since removed, or 
    events after the disk was imaged as causes of this effect.
    */
    
    I note you mentioned that other computers imaged at the same time as this 
    one had Norton Utilities installed. Norton certainly has the capability 
    with Speed Disk and WipeInfo to do exactly this. The user can configure 
    Norton to write system files to the end of the drive, or alternatively, 
    could configure Norton to write seldom used files to the end of the drive. 
    And speed disk can be configured to write any 8bit hex value (00-FF) to 
    all the unused space. Likewise, WipeInfo can be used to wipe the file 
    slack areas.
    
    Here are some bullets to stimulate thinking. Keep in mind that if you make 
    absolute statements in court like "leaving only ...", you'll get grilled 
    on details like this.
    
    In regard to stand alone utilities:
            Which stand alone defrag utilities can be used (run from a 
    floppy/CD) to defrag a FAT32 volume?
            For those that can be run from floppy or CD, which ones leave no 
    trace in the registry?
            Could the utility have been run from a mounted/mapped network 
    drive?
    
    In regard to "software since removed":
            Are there any traces of the software on the disk? 
            Are there any .lnk files in the "Recent" folder pointing to 
    nonexistent executables? 
            Which defrag/wipe utilities that could have been installed also 
    remove all traces of itself from the registry? 
            Don't most software programs leave some residual traces in the 
    registry even after being removed?
            If the defrag/wipe software was removed and there are no traces of 
    it on disk, how did it get wiped?
    
    In regard to "events after the disk was imaged":
            That should be pretty easy to address with DIBS image validation 
    (whatever they use).
    
    James
    ===============================
    
    James O. Holley
    Ernst & Young
    Litigation Advisory Services &
    Computer Forensic Services
    http://litigation.ey.com
    
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    ===============================
    
    
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