LBK is a local kernel based (kld) backdoor for FreeBSD 4.0 which provides a root shell if the TERM environment variable is set with the password.
You can download it from the following link: https://packetstormsecurity.com/files/download/23800/lbk.tar.gz
Source: https://packetstormsecurity.com/files/23800/lbk.tar.gz.html