Email tracing involves examining email header information to look for clues about where a message has been. This will be one of your more frequent responsibilities as a forensic investigator. You will often use audits or paper trails of email traffic as evidence in court. Many investigators recommend use of the tracert command. However, because of the dynamic nature of the Internet, tracert does not provide reliable, consistent, or accurate routing information for an email. To prove this, you can simply compare the routing from the email header to the results shown by tracert. The results are likely different, and the greater the distance between sender and receiver, the bigger the difference between the theoretical tracert results and the results determined from the actual routing information embedded in the header.
It may be useful to determine the ownership of the source email server for a message. If you need to manually find out to whom a given IP address is registered, a number of who is databases are available on the web. Here are just a few:
After a suspect comes to the authorities’ attention, your organization may ask you to monitor that person’s traffic. For example, administrators might request security checks on an employee who appears to be disgruntled or who has access to sensitive information. This employee’s email logs and network usage may, for example, show him or her sending innocent family photos to a Hotmail account, but no traffic coming back from that Hotmail account. These seemingly innocent photos might carry a steganographically hidden message, and so provide evidence of the employee’s part in corporate espionage.
Forensic email tracing is similar to traditional gumshoe detective work. It involves looking at each point through which an email passed. You work step by step back to the originating computer and, eventually, the perpetrator.