Web application security is complex due to a wide range of attacks at every layer of the application stack. Hackers use various reconnaissance methods like crawling target websites, mass vulnerability scans, open forums, and the dark web to find vulnerabilities. They then attempt to escalate privileges to access sensitive data and maintain remote access. Organizations need to implement strategies like secure coding practices, access management policies, patching, and monitoring to help protect their applications and data. Cloud security is a shared responsibility between the provider and customer.