Pro,
I'm not saying it's impossible. (Meg might, he knows his code better than I)
However, it is EXTREMELY unlikely that ULX/ULib was the cause of your exploit.
Make SURE you have an rcon password set in your config file. If you have a default, this might have been the issue.
However, to answer some of your questions....
How can i fix this
1)
a)Backup your banned_*.cfg files. Verify they only have IP or steamids first, and not any other 'exec' lines or code lines.
b)Totally delete all of your gmod9 server/game folders.
c)Scan your pc for worm/viruses using 2 different scanners. (3 or 4 free ones exist on the web. Panda/Bitdefender/Trendmicro to name 3 reliable ones I know)
d) Reinstall Gmod.
e) Reinstall only ULX 2.1/Ulib 1.1
e) Reinstall any maps you like, hold off on mods. (Yes, this sucks)
f) make SURE you have an rcon password set in your config file. If you have default, this might have been the issue.
g) Run server for a few days after doing answer 2
and make sure that that *($*#($# never comes back to my server ever.
2)
a) Once you have gmod9 and maps installed, add user to your banned_users.cfg (I think thats its name, should have other steamids there too) file. I don't remember of top of my head, but I think its format is STEAM:#:###### 0 ,where 0 is permanent
Also could they have hacked my computer too and be watching what iam saying here?
Y35 comrade. @ll your base belong to u5.
Joking.
Seriously, most worms don't watch that closely. Anything is possible though. See 1c above.