SOLDIERX.COM Nobody Can Stop Information Insemination

Hello.
How can I doing brute-force password hacking via Hydra?

I used "sudo nmap -sS -sV -vv -n -Pn -T5 my IP -p80 -oG - | grep 'open'" and the result is :

Host: my ip () Ports: 80/open/tcp//http//Allegro RomPager 4.07 UPnP|1.0 (ZyXEL ZyWALL 2)/

I know that "Hydra" with below syntax can do attack but use dictionary and I don't like it :

hydra -l {username} -P {password list path} -s {port} {IP Address} http-get /

I want to use Hydra without password dictionary.

Thank you.