There are many resources available to understand more about web and cloud application testing. Here is a list of resources:
- Kali Linux Web Penetration Testing Cookbook – Second Edition (Packt Publishing)
- OWASP Top 10 2017 – The Ten Most Critical Web Application Security Risks: https://www.owasp.org/images/7/72/OWASP_Top_10-2017_%28en%29.pdf.pdf
- OWASP Foundation: https://www.owasp.org/index.php/Main_Page