pafa7a is absolutely right, as usual !
They are many automate tools out there such as metasploit, sqlmap, hydra, acunetix and so on that may help you find a holes/suggestions, but none of them will save you from advanced attacks in a specific conditions.
For example you can be invulnerable to a simple sql injects, xss or any application related exploits, but one unsecured badly configured module/function can cause the same damage to you and open another holes.