Ettercap is a free and open source network security tool for man-in-the-middle attacks on a LAN.

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.

[2][3] Ettercap works by putting the network interface into promiscuous mode and by ARP poisoning the target machines.

Ettercap supports active and passive dissection of many protocols (including ciphered ones) and provides many features for network and host analysis.