Ettercap (software)

Ettercap is a free and open source network security tool for man-in-the-middle attacks on LAN. It can be used for computer network protocol analysis and security auditing. It runs on various Unix-like operating systems including Linux, Mac OS X, BSD and Solaris, and on Microsoft Windows. It is capable of intercepting traffic on a network segment, capturing passwords, and conducting active eavesdropping against a number of common protocols. Its original developers later founded Hacking Team.
Functionality.
Ettercap works by putting the network interface into promiscuous mode and by ARP poisoning the target machines. Thereby it can act as a 'man in the middle' and unleash various attacks on the victims. Ettercap has plugin support so that the features can be extended by adding new plugins.
Features.
Ettercap supports active and passive dissection of many protocols (including ciphered ones) and provides many features for network and host analysis. Ettercap offers four modes of operation:
In addition, the software also offers the following features:
Ettercap also has the ability to actively or passively find other poisoners on the LAN.