Search for security vulnerabilities on a website

Hello, I am looking for a specialist in security vulnerabilities for simple and infrequently visited websites. This person will have to list the most dangerous security vulnerabilities and give each time at least one solution to patch the vulnerabilitie.

In particular, you will need:
* test the site in SQL injections,
* attempt to upload files to the server
* attempt to make (minor) changes to the site
* and try to access our administration interface (the link will not be given and so it's OK if you can't)

The URK of the site will be given in private message.

THANKS