The "unplug the cord" dilemma

From: Omar Herrera (oherreraat_private)
Date: Thu Mar 27 2003 - 06:34:35 PST

  • Next message: Gary Flynn: "Re: The "unplug the cord" dilemma"

    
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    I was looking for documentation available discussing circumstances where 
    each of the following approaches is better:
    
       a) leave the system online/plugged to the network -> online 
    investigation
       b) unplug the system from network and shutdown -> offline forensics
       c) unplug the system from network and unplug from power source -> 
    offline forensics
    
    It can be argued that with any of these approaches you potentially loose 
    or alter evidence in some way; usually, approach c) is considered best in 
    procedures as it freezes the hard disk and makes impossible further 
    tampering (network connection information and data in volatile memory not 
    written to disk would be lost however). Approach a) is sometimes 
    necessary , for example, if there is an incident with a mission critical 
    system that cannot be unplugged from the network or shut down (even if 
    backups are available, sometimes bringing up a replacement system might 
    take just too long or be extremely difficult because of specialized 
    hardware availability).
    
    I intend to write a paper on the matter including a list of situations 
    where each approach is better suited but I want to include as well legal 
    implications for each approach (legal requirements from different 
    countries are welcome) and also recommended procedures for each approach 
    (for example, in an online investigation you might still use trusted 
    binaries saved on a floppy or cdrom rather than system binaries; if the 
    kernel was tampered with this might be of no use though). 
    
    Finally, I was dreaming of a system which had a kind of “forensic 
    hibernation mode”; currently I’m not aware of a system with this 
    capability (that would preserve memory an network connection sate while 
    freezing hard disks and, at the same time, being easy to do forensics on 
    it). If there is still no work in progress on this kind of systems I 
    would also like to discuss requirements for a standard that would allow 
    computer makers to include this capability on computer systems.
    
    All feedback, comments and suggestions will be greatly appreciated.
    
    Regards,
    
    Omar Herrera
    
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