you don't have to worry, just set a very strong RCON password if you are worried and don't use much, something like this:
PHP Code:
Zv$z=2g#$b:t>a(?TLuXJ6-i.Yv]w00CXyVAn:FRhiSmHkNy&(L<nX_}R+ZW1kD
and don't forget to set this in server.cfg
PHP Code:
sv_rcon_minfailures 2
sv_rcon_minfailuretime 600
sv_rcon_banpenalty 600
sv_rcon_maxfailures 3.