Trojans are malicious applications that pose themselves as legitimate software in order to trick users to install them. Once on the victim's machine, it may run any number of malicious process to steal vital information or inflict damage to other software.
This program is a hidden telnet server. It stays in the system as a hidden application and listens to socket 133 using TCP/IP protocol. By using that, a hacker may connect to a victim computer and get access to disk files and system resources.