• Criminal prosecutors. Incriminating documents related to homicide, financial fraud,
drug-related records.
• Insurance companies. Records of bill, cost, services to prove fraud in medical bills
and accidents.
• Law enforcement officials. Require assistance in search warrant preparation and in
handling seized computer equipment.
• Individuals. To support a possible claim of wrongful termination, sexual harassment,
or age discrimination.
The primary activities of network forensics are investigative in nature. The investigative
process encompasses the following:
• Identification
• Preservation
• Collection
• Examination
• Analysis
• Presentation
• Decision
In the following discussion, we focus on several important network forensic areas.
3. Attack Traceback and Attribution
When we face the cyber attacks, we can detect them and take countermeasures. For
instance, an intrusion detection system (IDS) can help detect attacks; we can update operating
systems to close potential backdoors; we can install antivirus software to defend against
many known viruses. Although in many cases we can detect attacks and mitigate their
damage, it is hard to find the real attackers or criminals. However, if we don’t trace back to
the attackers, they can always conceal themselves and launch new attacks. If we have
the ability to find and punish the attackers, we believe this will help significantly reduce the
attacks we face every day.
Why is traceback difficult in computer networks? One reason is that today’s Internet is
stateless. There is too much data in the Internet to record it all. For example, a typical router
only forwards the passed packets and does not care where they are from; a typical mail
transfer agent (MTA) simply relays emails to the next agent and never minds who is the
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