There are three general types of evidence:
--> Best evidence: can be presented in court in the original form (for example, an exact copy of a hard disk drive).
--> Corroborating evidence: tends to support a theory or an assumption deduced by some initial evidence. This corroborating evidence confirms the proposition.
--> Indirect or circumstantial evidence: extrapolation to a conclusion of fact (such as fingerprints, DNA evidence, and so on).

Section: Security Concepts

An ARP-based MITM attack is achieved when an attacker poisons the ARP cache of two devices with the MAC address of the attacker's network interface card (NIC). Once the ARP caches have been successfully poisoned, each victim device sends all its packets to the attacker when communicating to the other device and puts the attacker in the middle of the communications path between the two victim devices. It allows an attacker to easily monitor all communication between victim devices. The intent is to intercept and view the information being passed between the two victim devices and potentially introduce sessions and traffic between the two victim devices