CertiGuide to Security+  9  Chapter 5:  Operational/Organizational Security (Domain 5.0; 15%)       9  5.6  Computer Forensics

5.6  Computer Forensics 1 5.6.2  Preservation of Evidence

The Chain of Custody refers to the record of who had possession of each piece of evidence, for how long, and under what security conditions (i.e., what precautions were in place to prevent tampering with the evidence.)

Our research suggests that evidence is frequently not legally valid due to improper handling of evidence. Findings will be examined both for content and breakdowns in the chain of custody.

In short, documentation is everything -- and you cannot be too careful. Successful legal defense will look under every rock for a hole where evidence tampering could have occurred. The basic tenet for a criminal court case in many countries is, “beyond reasonable doubt.” Civil law is less restrictive going by “based on the preponderance of evidence. And if it appears that evidence was not properly documented, there is no evidence to ponder.”

To give you an idea of what we mean: Locking hard drives involved in an incident in a lockbox in a safe, and requiring the presence of two different people to both remove the lockbox from the safe and open the lockbox, is not necessarily overkill. You want to remove as much doubt as you can that anything could have happened to the evidence between the time it was involved in the incident and the time it is presented in court.

5.6  Computer Forensics 1 5.6.2  Preservation of Evidence