Forensic Examination of Digital Evidence

SPECIAL REPORT / APR. 04
■ Analyzing file metadata, the content of the user-created file containing data additional
to that presented to the user, typically viewed through the application that created it.
For example, files created with word processing applications may include authorship,
time last edited, number of times edited, and where they were printed or saved.
Ownership and possession
In some instances it may be essential to identify the individual(s) who created, modified,
or accessed a file. It may also be important to determine ownership and knowledgeable
possession of the questioned data. Elements of knowledgeable possession may be
based on the analysis described above, including one or more of the following factors.
■ Placing the subject at the computer at a particular date and time may help determine
ownership and possession (timeframe analysis).
■ Files of interest may be located in nondefault locations (e.g., user-created directory
named “child porn”) (application and file analysis).
■ The file name itself may be of evidentiary value and also may indicate the contents of
the file (application and file analysis).
■ Hidden data may indicate a deliberate attempt to avoid detection (hidden data analysis).
■ If the passwords needed to gain access to encrypted and password-protected files are
recovered, the passwords themselves may indicate possession or ownership (hidden
data analysis).
■ Contents of a file may indicate ownership or possession by containing information
specific to a user (application and file analysis).
Step 4. Conclusion
In and of themselves, results obtained from any one of these steps may not be sufficient
to draw a conclusion. When viewed as a whole, however, associations between
individual results may provide a more complete picture. As a final step in the examination
process, be sure to consider the results of the extraction and analysis in their
entirety.
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