How to test website's security ?

Hi,

Everything is in the title : how can i test the security of a forum please ? Is there sites or programs (for a basic/medium user )
We don't know how to proceed to be sure that "standard" attacks could be prevented.
I've tried an old firefox's plugin who test sql injection and xss : i've got 404 error so i don't know what to do for a better protection.

Many thanks.

 

try Nessus

 

Thanks, i'm going to try it.

 

There's Zerodayscan and Sucuri Site Check as well.

 

Well thanks, i've got some job for this weekend.

 

There's also LinkScanner:

http://linkscanner.explabs.com/linkscanner/default.aspx

and SiteAdvisor:

http://www.siteadvisor.com/analysis/

Although a word of caution. I once read somewhere that these types of sites are not always reliable.

 

Excuse me but i want to test my website against hackers, not to view the rate. The tools you provide me can analyse the website or just give me the reputation ?

 

try this
http://www.acunetix.com/

 

Already tested, thanks

I've found some blogs talking about security and how to protect, so i'm working on. And i hope it would be enough.