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.
Backage is a backdoor Trojan horse that allows unauthorized access to a compromised computer.
Backage is written in Visual Basic. The default ports are 5333 (TCP) and 411(TCP).