Ncrack is a high-speed network authentication cracking tool. It was
built to help companies secure their networks by proactively testing all
their hosts and networking devices for poor passwords.

Security professionals also rely on Ncrack when auditing their clients.
Ncrack was designed using a modular approach, a command-line syntax
similar to Nmap and a dynamic engine that can adapt its behaviour based
on network feedback. It allows for rapid, yet reliable large-scale
auditing of multiple hosts.

Ncrack's features include a very flexible interface granting the user
full control of network operations, allowing for very sophisticated
bruteforcing attacks, timing templates for ease of use, runtime
interaction similar to Nmap's and many more. Protocols supported include
RDP, SSH, http(s), SMB, pop3(s), VNC, FTP, and telnet.

Be sure to read the Ncrack man page (https://nmap.org/ncrack/man.html)
to fully understand Ncrack usage.