With your blessing, I will attempt to hack your website.
I will try to steal your usernames, passwords, software versions, upload files, create a man in the middle scenario, download user information, redirect your website and/or whatever additional mischief a real world hacker will do if you give them an opportunity.
This can be an active exercise, or passive (no files are changed).
Afterwards I will work with you to fix anything that I was able to do & close security holes. I will also suggest alternatives for vulnerabilities that cannot be fixed.