CCTT, "Covert Channel Tunneling Tool" is a tool presenting several exploitation techniques allowing the creation of arbitrary data transfer channels in the data streams authorized by a network access control system.
CCTT enables the creation of communication channels through NACS to create data streams which can:
get an external server shell from within the internal network;
give a shell from a box located within the internal network to an external server;
setting a TCP/UDP/HTTP CONNECT | POST channel allowing TCP data streams (SSH, SMTP, POP, etc.) between an external server and a box from within the internal network.