see my hacked guestbook now

www.chaucingo.com/libro.html

can someboddy help. so next time it wont happen again. how can i stop this user.?
and the message of the webpage says:

who said that i could not hack this

HaCkEd By DaRkNeSs

A mexican hacker was here.

They didn't hack it. They abused the fact you have HTML turned on.

i read about the html code active, but it was not active. i update to 2.3.3 and this time this person post this code

"><iframe src="http://www.hackers-of-mexico.cjb.net/">
http://www.hackers-of-mexico.cjb.net/">

now I am worried, is this person able to attack the guestbook with ferocity and damage the database or the code of the guestbook or even worse, obtain the admin password? :?: :?:

i hate this person allready :evil:

Thi sperson has no understanding of the guestbook or how it works. They read about the exploit on a site somewhere and is just following step by step instructions. 2.3.3 is secure against all known exploits so long as you have HTML turned off.