hydra software package provides very fast network logon cracker, you can install in your Debian 9 (Stretch) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install hydra
hydra is installed in your system.
Make ensure the hydra package were installed using the commands given below,
$ sudo dpkg-query -l | grep hydra *
You will get with hydra package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Network |
| Package | hydra |
| Version | 8.3-1 |
| Description | very fast network logon cracker |
| Sub Section | Net |