Which tool to choose for auditing a web application?

Question

Information Security

Hello!
The task is to conduct an audit and search for vulnerabilities in a web application.
As it turned out, the application is self-written. Working with OWASP gave nothing.
What analysis tools would you recommend? Testing literature is also welcome.

Answer 1

Hands + head
We take our heads in our hands and check all the functions for processing GET / POST / Cookies - for filtering incoming data and correct processing.