SAMP account hack

Completely invalid statement. Do not listen to this individual claiming themself to be a "SA-MP expert".

You can NOT decrypt a hash. A hashed password does not equal an encrypted password. Encrypting passwords is retarded in itself because you need a key, which will sit visible in your gamemode.

Even with access to the hashed passwords it'll take you far too long to run a rainbow table over the hashed password, have the server developer applied salts and used a proper hashing technique or simply used bcrypt with a cost of over 10 (bcrypt does not require salts, but is still infinitely better than any other hashing technique at the point of posting this).

Unless you want to spend several years (bcrypt) finding someone's password out from a leaked database, your only left option is finding an exploit in the login/register system or social engineering.

Conclusion: No.

Well on the community that I play on some guy got banned and blacklisted for hacking people's accounts. So it must be possible.
(Some kind of kid just hacked people's accounts on the community I play on, named XSS Server. It is a really secured server so that kid must be a genius.)

You can hack an account with bruteforce bot, so that bot will try every combination to login in. Its same to rcon bruteforce. But this method take so many time. Also password information (hash) is stored in server database wich is hard to hack it, if you dont know same host informtion.

Could you explain me exactly how Tu use those things and which programs pls?