The Rules for Computer Forensics
by Colm Murphy - Technical Director of Espion - Friday, 20 July 2007.
The recovery of evidence from electronic devices is fast becoming another component of many the IT Managerís remit. Electronic evidence gathered is often valuable evidence and as such should be treated in the same manner as traditional forensic evidence - with respect and care.

Essentially, this area is known as computer forensics and can be described as the scientific examination and analysis of data held on, or retrieved from, computer storage media in such a way that the information can be used as evidence in a court of law. Subject matter can include:
  • the secure collection of computer data
  • the examination of suspect data to determine details such as origin and content
  • the presentation of computer based information to courts of law (if necessary)
  • the application of a country's laws to computer practice.
In short, the objectives of a forensics analysis are to, determine what happened, the extent of the problem, determine who was responsible and present this information as evidence in court if required.

It is used by internal investigators of public and private organisations for a variety of reasons, in particular where a computer user is suspected of a breach of organisational policy. Indeed, in the past couple of years awareness amongst the legal community in Ireland of the need for professional computer forensic services and equipment has increased substantially.

The methods of recovering electronic evidence whilst maintaining evidential continuity and integrity may seem complex and costly, but experience has shown that, if dealt with correctly, it will produce evidence that is both compelling and cost effective.

When talking about computer forensics, it is easy to get caught up in the technical minutiae - the bits and the bytes, the ones and the zeros, slackspace and pagefiles. Given the language used by many forensic investigators it is little wonder that many people consider it to be a black art, forever damned to the world of the ponytails.

In reality however, digital forensics is concerned primarily with forensic procedures, rules of evidence and legal processes. The principal reason given that forensic evidence fails to deliver in a court is not the technical merit of the evidence itself, but rather issues relating to how it was gathered, who gathered it, what training and experience they have, chain of custody, proper documentation, and even, believe it or not, the storage facilities used. A certain case here in Ireland springs to mind, where the evidence storage facility was brought into question. Who had access to it? What security measures are in place to ensure only authorised personnel have access to the evidence? What chain of custody documentation is kept? These are ultimately the key questions and are among the crucial considerations for any IT team if they find themselves central to an internal investigation.

Although the document is not intended to be a definitive manual of every single operation that may take place during an investigation, it does provide some first-rate guidance and advice. Interestingly, the thrust of the guide is about forensic procedures, rules of evidence and legal process, and is a great resource for anyone tasked with drafting incident response policies and procedures.

From the outset, I would like readers to note that when tasked (usually by the HR department) with conducting an investigation relating to computer equipment there are some key Ďrulesí to be followed:


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