If it is web-based attacks which are of interest to you at the moment, consider looking into the OWASP Top 10, and also a web application scanner such as Nikto.

If it is web-based attacks which are of interest to you at the moment, consider looking into the OWASP Top 10, and also a web application scanner such as Nikto. These should give you a good insight and prompt you with some further avenues to explore.