MODERN WEB APPLICATION SECURITY: A COMPREHENSIVE ANALYSIS OF VULNERABILITIES, EXPLOIT CHAINS, AND PREVENTION STRATEGIES

Web applications which use cloud-native architectures in their distributed operational environments have their attack surface area increased. The research study establishes a complete system of web application security weaknesses which matches the DOA Top 10 list (2025) and the API Security Top 10 list (2023) while including additional threats from supply-chain operations and cloud-native environments. The empirical research shows that 77% of web application security breaches occur through stolen credentials, while 21% of breaches happen due to brute-force attacks and 13% of breaches occur through direct vulnerability exploitation according to Verizon DBIR 2024. The OWASP findings show that 3.73% of assessed applications display Broken Access Control while 3.00% show Security Misconfiguration and 3.80% exhibit Cryptographic Failures which demonstrates ongoing fundamental security vulnerabilities. The research develops multi-phase exploitation models which begin with actual security breaches that occurred between 2018 and 2026 to show how attackers begin their intrusion attempts which lead to extensive data loss incidents. The evaluation of tools shows that SAST DAST and runtime systems demonstrate different detection abilities because both false positives and integration difficulties act as major drawbacks. The research establishes a defense framework which combines secure SDLC methods with DevSecOps pipeline security and runtime security assessment. The results show that identity theft and system misconfiguration errors represent the main causes of contemporary web security breaches which require organizations to implement complete security frameworks.