Sniffer Attack
A sniffer is an application or device that can read, monitor, and capture network data exchanges and read network packets. If the packets are not encrypted, a sniffer provides a full view of the data inside the packet. Even encapsulated (tunneled) packets can be broken open and read unless they are encrypted and the attacker does not have access to the key.
Using a sniffer, an attacker can do any of the following:
Analyze your network and gain information to eventually cause your network to crash or to become corrupted.
Read your communications.