In couple of days i will re-install Linux (Ubuntu-gnome) and I'm interested to start learning and testing security programs.Anyone here can suggests me any sec program?
Note 1.0: I don't know if this is on the right category xD.
The place to start is kali linux, but it is a bootable flash drive. I suppose you could run it in a virtual box.
The best way to lean to defend a system is to first learn how to attack a system.
Once you get an idea of the vulnerabilities in different systems, you can research how to defend them.
Kali is definitely worth checking out, as mentioned by @Tjj226_Angel. I would suggest you have a look on Youtube for tutorials.
Link: https://www.youtube.com/results?search_query=kali+linux+security+tools
If you find any videos you want to keep; Link: http://en.savefrom.net/
Since your installing ubuntu you could familiarize yourself with apparmor & iptables for starters.