I am wondering out of OWASP top 10 (A1-A10) which all can be automated. Is it possible to automate their testing using Selenium, if not which tool can be used to automate them ? Also are there any documents or guidelines or any examples that can be followed or referred.
Thanks in advance.
I'd say:
Finding security vulnerabilities is hard, automation should be seen as a way to cut down the time and effort spent doing manual testing rather than replacing it. One of the advantages of automated testing is that you can do it at any time (eg as part of CI/CD) rather than waiting until near the end and getting the pentesters in.
In all cases manual verification of any potential vulnerabilities found using automation is important.
Have a look at https://www.owasp.org/index.php/ZAPpingTheTop10 which is focused on ZAP. Automation is definitely a focus for ZAP (and one of the key ways we use it in Mozilla) and not surprisingly its something I'd recommend using (I'm the ZAP project lead;)